Isidor Rayner
United States Senator from Maryland
In office March 4, 1905 – November 25, 1912
Preceded by	Louis E. McComas
Succeeded by	William P. Jackson
Member of the U.S. House of Representatives from Maryland's 4th district
In office March 4, 1887 – March 3, 1889
Preceded by	John Van Lear Findlay
Succeeded by	Henry Stockbridge, Jr.
In office March 4, 1891 – March 3, 1895
Preceded by	Henry Stockbridge, Jr.
Succeeded by	John K. Cowen
Attorney General of Maryland
In office 1899–1903
Governor	Lloyd Lowndes Jr. John W. Smith
Preceded by	George Riggs Gaither Jr.
Succeeded by	William Shepard Bryan Jr.
Member of the Maryland Senate
In office 1885-1886
Member of the Maryland House of Delegates
In office 1878-1884
Personal details
Born	(1850-04-11)April 11, 1850 Baltimore, Maryland, U.S.
Died	November 25, 1912(1912-11-25) (aged 62) Washington, D.C., U.S.
Resting place	Rock Creek Cemetery Washington, D.C., U.S.
Political party	Democratic

Isidor Rayner (April 11, 1850 – November 25, 1912) was a Democratic member of the United States Senate, representing the State of Maryland from 1905 to 1912. He also represented the Fourth Congressional District of Maryland from 1887 to 1889, and 1891 to 1895.

Rayner was born into a German-Jewish family^[1] in Baltimore, Maryland, and attended local private schools. He later attended the University of Maryland, Baltimore, and the University of Virginia. He began to study law and was admitted to the Maryland bar in 1871.

Rayner was elected to the Maryland House of Delegates and served from 1878 to 1884. In 1885, he was elected to the Maryland State Senate, serving one year until 1886.

Rayner was elected the same year to the 50th United States Congress. He was an unsuccessful candidate for reelection in 1888 to the 51st Congress, but was victorious in the next two elections to the 52nd and 53rd Congresses. He declined to be a candidate for renomination in 1894.

Five years later in 1899, Rayner was chosen to be the Attorney General of Maryland, serving until 1903. He was elected as a Democrat in 1905 to the U.S. Senate, and was reelected again in 1911. While senator, he served as chairman of the Committee on Indian Depredations (Sixty-second Congress).

In 1912, Rayner died in Washington, D.C., while serving as senator. He is buried at Rock Creek Cemetery.

• List of Jewish American jurists
• List of Jewish members of the United States Congress
• List of United States Congress members who died in office (1900–49)

• United States Congress. "Isidor Rayner (id: R000086)". Biographical Directory of the United States Congress.

• Works by or about Isidor Rayner at the Internet Archive
• Isidor Rayner, late a senator from Maryland, Memorial addresses delivered in the House of Representatives and Senate frontispiece 1914