Justice Stevens
delivered the opinion of the Court.
Baltimore police officers obtained and executed a warrant to search the person of Lawrence McWebb and “the premises known as 2036 Park Avenue third floor apartment.”1 When the police applied for the warrant and when they conducted the search pursuant to the warrant, they reasonably believed that there was only one apartment on the premises described in the warrant. In fact, the third floor was divided into two apartments, one occupied by McWebb and one by respondent Garrison. Before the officers executing the warrant became aware that they were in a separate apartment occupied by respondent, they had discovered the contraband that provided the basis for respondent’s conviction for violating Maryland’s Controlled Substances Act. The question presented is whether the seizure of that contraband was prohibited by the Fourth Amendment.
The trial court denied respondent’s motion to suppress the evidence seized from his apartment, App. 46, and the Mary[81]*81land Court of Special Appeals affirmed. 58 Md. App. 417, 473 A. 2d 514 (1984). The Court of Appeals of Maryland reversed and remanded with instructions to remand the case for a new trial. 303 Md. 385, 494 A. 2d 193 (1985).
There is no question that the warrant was valid and was supported by probable cause. Id., at 392, 494 A. 2d, at 196. The trial court found, and the two appellate courts did not dispute, that after making a reasonable investigation, including a verification of information obtained from a reliable informant, an exterior examination of the three-story building at 2036 Park Avenue, and an inquiry of the utility company, the officer who obtained the warrant reasonably concluded that there was only one apartment on the third floor and that it was occupied by McWebb. App. 41; 58 Md. App., at 433, 473 A. 2d, at 522; 303 Md., at 387-390, 494 A. 2d, at 194-195. When six Baltimore police officers executed the warrant, they fortuitously encountered McWebb in front of the building and used his key to gain admittance to the first-floor hallway and to the locked door at the top of the stairs to the third floor. As they entered the vestibule on the third floor, they encountered respondent, who was standing in the hallway area. The police could see into the interior of both Mc-Webb’s apartment to the left and respondent’s to the right, for the doors to both were open. Only after respondent’s apartment had been entered and heroin, cash, and drug paraphernalia had been found did any of the officers realize that the third floor contained two apartments. App. 41-46. As soon as they became aware of that fact, the search was discontinued. Id., at 32, 39. All of the officers reasonably believed that they were searching McWebb’s apartment.2 No further search of respondent’s apartment was made.
[82]*82The matter on which there is a difference of opinion concerns the proper interpretation of the warrant. A literal reading of its plain language, as well as the language used in the application for the warrant, indicates that it was intended to authorize a search of the entire third floor.3 This is the construction adopted by the intermediate appellate court, see 58 Md. App., at 419, 473 A. 2d, at 515, and it also appears to be the construction adopted by the trial judge. See App. 41. One sentence in the trial judge’s oral opinion, however, lends support to the construction adopted by the Court of Appeals, namely, that the warrant authorized a search of McWebb’s apartment only.4 Under that interpretation, the Court of [83]*83Appeals concluded that the warrant did not authorize the search of respondent’s apartment and the police had no justification for making a warrantless entry into his premises.5
The opinion of the Maryland Court of Appeals relies on Article 26 of the Maryland Declaration of Rights6 and Maryland cases as well as the Fourth Amendment to the Federal Constitution and federal cases. Rather than containing any “plain statement” that the decision rests upon adequate and independent state grounds, see Michigan v. Long, 463 U. S. 1032, 1042 (1983), the opinion indicates that the Maryland constitutional provision is construed in pari materia with the
[84]*84Fourth Amendment.7 We therefore have jurisdiction. Because the result that the Court of Appeals reached did not appear to be required by the Fourth Amendment, we granted certiorari. 475 U. S. 1009 (1986). We reverse.
In our view, the case presents two separate constitutional issues, one concerning the validity of the warrant and the other concerning the reasonableness of the manner in which it was executed. See Dalia v. United States, 441 U. S. 238, 258 (1979). We shall discuss the questions separately.
I-H
The Warrant Clause of the Fourth Amendment categorically prohibits the issuance of any warrant except one “particularly describing the place to be searched and the persons or things to be seized.” The manifest purpose of this particularity requirement was to prevent general searches. By limiting the authorization to search to the specific areas and things for which there is probable cause to search, the requirement ensures that the search will be carefully tailored to its justifications, and will not take on the character of the wide-ranging exploratory searches the Framers intended to prohibit.8 Thus, the scope of a lawful search is “defined by the object of the search and the places in which there is probable cause to believe that it may be found. Just as probable cause to believe that a stolen lawnmower may be found in a garage will not support a warrant to search an upstairs bedroom, probable cause to believe that undocumented aliens are being transported in a van will not justify a warrantless [85]*85search of a suitcase.” United States v. Ross, 456 U. S. 798, 824 (1982).
In this case there is no claim that the “persons or things to be seized” were inadequately described or that there was no probable cause to believe that those things might be found in “the place to be searched” as it was described in the warrant. With the benefit of hindsight, however, we now know that the description of that place was broader than appropriate because it was based on the mistaken belief that there was only one apartment on the third floor of the building at 2036 Park Avenue. The question is whether that factual mistake invalidated a warrant that undoubtedly would have been valid if it had reflected a completely accurate understanding of the building’s floor plan.
Plainly, if the officers had known, or even if they should have known, that there were two separate dwelling units on the third floor of 2036 Park Avenue, they would have been obligated to exclude respondent’s apartment from the scope of the requested warrant. But we must judge the constitutionality of their conduct in light of the information available to them at the time they acted. Those items of evidence that emerge after the warrant is issued have no bearing on whether or not a warrant was validly issued.9
Free access — add to your briefcase to read the full text and ask questions with AI
Justice Stevens
delivered the opinion of the Court.
Baltimore police officers obtained and executed a warrant to search the person of Lawrence McWebb and “the premises known as 2036 Park Avenue third floor apartment.”1 When the police applied for the warrant and when they conducted the search pursuant to the warrant, they reasonably believed that there was only one apartment on the premises described in the warrant. In fact, the third floor was divided into two apartments, one occupied by McWebb and one by respondent Garrison. Before the officers executing the warrant became aware that they were in a separate apartment occupied by respondent, they had discovered the contraband that provided the basis for respondent’s conviction for violating Maryland’s Controlled Substances Act. The question presented is whether the seizure of that contraband was prohibited by the Fourth Amendment.
The trial court denied respondent’s motion to suppress the evidence seized from his apartment, App. 46, and the Mary[81]*81land Court of Special Appeals affirmed. 58 Md. App. 417, 473 A. 2d 514 (1984). The Court of Appeals of Maryland reversed and remanded with instructions to remand the case for a new trial. 303 Md. 385, 494 A. 2d 193 (1985).
There is no question that the warrant was valid and was supported by probable cause. Id., at 392, 494 A. 2d, at 196. The trial court found, and the two appellate courts did not dispute, that after making a reasonable investigation, including a verification of information obtained from a reliable informant, an exterior examination of the three-story building at 2036 Park Avenue, and an inquiry of the utility company, the officer who obtained the warrant reasonably concluded that there was only one apartment on the third floor and that it was occupied by McWebb. App. 41; 58 Md. App., at 433, 473 A. 2d, at 522; 303 Md., at 387-390, 494 A. 2d, at 194-195. When six Baltimore police officers executed the warrant, they fortuitously encountered McWebb in front of the building and used his key to gain admittance to the first-floor hallway and to the locked door at the top of the stairs to the third floor. As they entered the vestibule on the third floor, they encountered respondent, who was standing in the hallway area. The police could see into the interior of both Mc-Webb’s apartment to the left and respondent’s to the right, for the doors to both were open. Only after respondent’s apartment had been entered and heroin, cash, and drug paraphernalia had been found did any of the officers realize that the third floor contained two apartments. App. 41-46. As soon as they became aware of that fact, the search was discontinued. Id., at 32, 39. All of the officers reasonably believed that they were searching McWebb’s apartment.2 No further search of respondent’s apartment was made.
[82]*82The matter on which there is a difference of opinion concerns the proper interpretation of the warrant. A literal reading of its plain language, as well as the language used in the application for the warrant, indicates that it was intended to authorize a search of the entire third floor.3 This is the construction adopted by the intermediate appellate court, see 58 Md. App., at 419, 473 A. 2d, at 515, and it also appears to be the construction adopted by the trial judge. See App. 41. One sentence in the trial judge’s oral opinion, however, lends support to the construction adopted by the Court of Appeals, namely, that the warrant authorized a search of McWebb’s apartment only.4 Under that interpretation, the Court of [83]*83Appeals concluded that the warrant did not authorize the search of respondent’s apartment and the police had no justification for making a warrantless entry into his premises.5
The opinion of the Maryland Court of Appeals relies on Article 26 of the Maryland Declaration of Rights6 and Maryland cases as well as the Fourth Amendment to the Federal Constitution and federal cases. Rather than containing any “plain statement” that the decision rests upon adequate and independent state grounds, see Michigan v. Long, 463 U. S. 1032, 1042 (1983), the opinion indicates that the Maryland constitutional provision is construed in pari materia with the
[84]*84Fourth Amendment.7 We therefore have jurisdiction. Because the result that the Court of Appeals reached did not appear to be required by the Fourth Amendment, we granted certiorari. 475 U. S. 1009 (1986). We reverse.
In our view, the case presents two separate constitutional issues, one concerning the validity of the warrant and the other concerning the reasonableness of the manner in which it was executed. See Dalia v. United States, 441 U. S. 238, 258 (1979). We shall discuss the questions separately.
I-H
The Warrant Clause of the Fourth Amendment categorically prohibits the issuance of any warrant except one “particularly describing the place to be searched and the persons or things to be seized.” The manifest purpose of this particularity requirement was to prevent general searches. By limiting the authorization to search to the specific areas and things for which there is probable cause to search, the requirement ensures that the search will be carefully tailored to its justifications, and will not take on the character of the wide-ranging exploratory searches the Framers intended to prohibit.8 Thus, the scope of a lawful search is “defined by the object of the search and the places in which there is probable cause to believe that it may be found. Just as probable cause to believe that a stolen lawnmower may be found in a garage will not support a warrant to search an upstairs bedroom, probable cause to believe that undocumented aliens are being transported in a van will not justify a warrantless [85]*85search of a suitcase.” United States v. Ross, 456 U. S. 798, 824 (1982).
In this case there is no claim that the “persons or things to be seized” were inadequately described or that there was no probable cause to believe that those things might be found in “the place to be searched” as it was described in the warrant. With the benefit of hindsight, however, we now know that the description of that place was broader than appropriate because it was based on the mistaken belief that there was only one apartment on the third floor of the building at 2036 Park Avenue. The question is whether that factual mistake invalidated a warrant that undoubtedly would have been valid if it had reflected a completely accurate understanding of the building’s floor plan.
Plainly, if the officers had known, or even if they should have known, that there were two separate dwelling units on the third floor of 2036 Park Avenue, they would have been obligated to exclude respondent’s apartment from the scope of the requested warrant. But we must judge the constitutionality of their conduct in light of the information available to them at the time they acted. Those items of evidence that emerge after the warrant is issued have no bearing on whether or not a warrant was validly issued.9 Just as the discovery of contraband cannot validate a warrant invalid when issued, so is it equally clear that the discovery of facts demonstrating that a valid warrant was unnecessarily broad does not retroactively invalidate the warrant. The validity of the warrant must be assessed on the basis of the information that the officers disclosed, or had a duty to discover and to disclose, to the issuing Magistrate.10 On the basis of that [86]*86information, we agree with the conclusion of all three Maryland courts that the warrant, insofar as it authorized a search that turned out to be ambiguous in scope, was valid when it issued.
II
The question whether the execution of the warrant violated respondent’s constitutional right to be secure in his home is somewhat less clear. We have no difficulty concluding that the officers’ entry into the third-floor common area was legal; they carried a warrant for those premises, and they were accompanied by McWebb, who provided the key that they used to open the door giving access to the third-floor common area. If the officers had known, or should have known, that the third floor contained two apartments before they entered the living quarters on the third floor, and thus had been aware of the error in the warrant, they would have been obligated to limit their search to McWebb’s apart[87]*87ment. Moreover, as the officers recognized, they were required to discontinue the search of respondent’s apartment as soon as they discovered that there were two separate units on the third floor and therefore were put on notice of the risk that they might be in a unit erroneously included within the terms of the warrant. The officers’ conduct and the limits of the search were based on the information available as the search proceeded. While the purposes justifying a police search strictly limit the permissible extent of the search, the Court has also recognized the need to allow some latitude for honest mistakes that are made by officers in the dangerous and difficult process of making arrests and executing search warrants.11
In Hill v. California, 401 U. S. 797 (1971), we considered the validity of the arrest of a man named Miller based on the mistaken belief that he was Hill. The police had probable cause to arrest Hill and they in good faith believed that Miller was Hill when they found him in Hill’s apartment. As we explained:
“The upshot was that the officers in good faith believed Miller was Hill and arrested him. They Were quite wrong as it turned out, and subjective good-faith belief would not in itself justify either the arrest or the subsequent search. But sufficient probability, not certainty, is the touchstone of reasonableness under the Fourth Amendment and on the record before us the officers’ mistake was understandable and the arrest a reasonable response to the situation facing them at the time.” Id., at 803-804.
While Hill involved an arrest without a warrant, its underlying rationale that an officer’s reasonable misidentification [88]*88of a person does not invalidate a valid arrest is equally applicable to an officer’s reasonable failure to appreciate that a valid warrant describes too broadly the premises to be searched. Under the reasoning in Hill, the validity of the search of respondent’s apartment pursuant to a warrant authorizing the search of the entire third floor depends on whether the officers’ failure to realize the overbreadth of the warrant was objectively understandable and reasonable. Here it unquestionably was. The objective facts available to the officers at the time suggested no distinction between McWebb’s apartment and the third-floor premises.12
For that reason, the officers properly responded to the command contained in a valid warrant even if the warrant is interpreted as authorizing a search limited to McWebb’s apartment rather than the entire third floor. Prior to the officers’ discovery of the factual mistake, they perceived McWebb’s apartment and the third-floor premises as one and the same; therefore their execution of the warrant reasonably included the entire third floor.13 Under either interpretation of the warrant, the officers’ conduct was consistent with a reasonable effort to ascertain and identify the place intended to be searched within the meaning of the Fourth Amend[89]*89ment.14 Cf. Steele v. United States, 267 U. S. 498, 503 (1925).
The judgment of the Court of Appeals is reversed, and the case is remanded for further proceedings not inconsistent with this opinion.
It is so ordered.