Hello Alan, my name is***** and I am an attorney with over 15 years of experience. I believe you are referring to the 30/60 day rule. Essentially it states when a person enters on a B-2 nonimmigrant visa claiming to be a visitor and within 30 days marries, USCIS may presume that the applicant misrepresented his or her intentions in seeking a visa or entry. This is actually found in the Foreign Affairs Manual (9 FAM 302.9-4(B)(3)(g)(1). If it is between 30 and 60 days there is no presumption. The actual regulation reads:
(U) Applying 30/60 Day Rule When Alien Violates Status: You should apply the 30/60-day rule if an alien states on his or her application for a B visa, or informs an immigration officer at the port of entry (POE), that the purpose of his or her visit is consistent with B status and then violates such status by:
(a) (U) Actively seeking unauthorized employment and, subsequently, becomes engaged in such employment;
(b) (U) Enrolling in a full course of academic study without the benefit of the appropriate change of status;
(c) (U) Marrying and taking up permanent residence; or
(d) (U) Undertaking any other activity for which a change of status or an adjustment of status would be required, without the benefit of such a change or adjustment.
(3) (U) Inconsistent Conduct Within 30 Days of Entry: If an alien violates his or her nonimmigrant status in a manner described in 9 FAM 302.9-4(B)(3) paragraph g(2) within 30 days of entry, you may presume that the applicant misrepresented his or her intention in seeking a visa or entry. For a finding of an inadmissibility for inconsistent conduct within 30 days of entry, you must request an AO from CA/VO/L/A.
(4) (U) After 30 Days But Within 60 Days: If an alien violates his or her nonimmigrant status more than 30 days but less than 60 days after entry into the United States, no presumption of misrepresentation arises. However, if the facts in the case give you reasonable belief that the alien misrepresented his or her intent, then you must give the alien the opportunity to present countervailing evidence. If you do not find such evidence to be persuasive, you must request an AO from CA/VO/L/A. (See 9 FAM 302.9-4(C)(2)).
This means you should wait at least 60 days before you marry if that is what you decide to do. Please let me know if you have any further questions. Thanks!