The Chicago Manual of Style, like both MLA and APA, defers to The Bluebook for legal citations.
Legal publications only need to be cited in the notes, not the bibliography (unless you have a secondary publication, like a book in which the legal publication appears, in which case CMOS takes over).
Laws are initially collected in the United States Statutes at Large (Stat.), and later are incorporated into the United States Code (U.S.C.). These publications are broadly called reporters.
1. Name of the Bill, vol# Reporter Name series# (year), url.
1. Homeland Security Act of 2002, Pub. L. No. 107-296, 116 Stat. 2135 (2012).
2. Homeland Security Act of 2002, 6 U.S.C. §101 (2012).
3. Chinese Exclusion Act, 22 Stat. 58 (1882), https://www.ourdocuments.gov/doc.php?flash=true&doc=47&page=transcript.
1. Name of the Bill, Bill No., No. of the Congress, section # (year).
1. State v. Griffin, 211 W. Va. 508, 566 S.E.2d 645 (2002), http://www.courtswv.gov/supreme-court/docs/spring2002/30433.htm.
US Supreme Court Cases:
1. Citizens United v. Federal Election Comm'n, 558 U.S. 310 (2010).
2. Citizens United, 558 U.S. at 322.
3. Obergefell v. Hodges, 135 S. Ct. 2584 (2015).
With a Court Specified before Year:
1. Profit Sharing Plan v. Mbank Dallas, N.A., 683 F.Supp. 592 (N.D. Tex. 1988).
1. Published Title of the Recorded Testimony, Before the Relevant Committee, number of the Congress, page# (year) (Speaker's Name, Title and Affiliation).
1. Homeland Security Act of 2002: Hearings on H.R. 5005, Day 3, Before the Select Comm. on Homeland Security, 107th Cong. 203 (2002) (statement of David Walker, Comptroller General of the United States).
1. Sender First Name Surname to Recipient First Name Surname, memorandum, "Subject of Memo," date, Collection Information, url.
2. Sender to Recipient, date.
Sender Surname, First Name. Sender First Name Surname to Recipient First Name Surname, memorandum, "Subject of Memo," date. Collection Information. url.
1. William L. Stearman to Henry Kissinger, memorandum, "Current Military Situation in Vietnam," Aug. 9, 1974, Presidential Country Files: East Asia and the Pacific, Gerald R. Ford Presidential Library & Museum, https://www.fordlibrarymuseum.gov/library/exhibits/vietnam/032400069-001.pdf.
2. Stearman to Kissinger, Aug. 9, 1974.
Stearman, William L. William L. Stearman to Henry Kissinger, memorandum, "Current Military Situation in Vietnam," Aug. 9, 1974. Presidential Country Files: East Asia and the Pacific. Gerald R. Ford Presidential Library & Museum. https://www.fordlibrarymuseum.gov/library/exhibits/vietnam/032400069-001.pdf.