James Gaven Field (February 24, 1826 – October 12, 1901) was an American politician in California and Virginia, who was also a businessman, government clerk, and Confederate major.

In addition to his federal government job, he became the secretary of the convention that framed the first constitution of the state of California in 1850.

In 1879 Field argued Ex Parte Virginia before the U.S. Supreme Court, however he failed to convince the justices that Congress lacked authority to require blacks on trial juries.

Field campaigned in the southern and border states and in support of the party's radical reform platform.

At a mid-July speech in Gordonsville, in Orange County, he compared the revolutionary impulse of Populism with the American Revolution of 1776 and advised his audience to "Read your Bibles Sunday and the Omaha platform every day in the week.