James Harvey Slater (December 28, 1826 – January 28, 1899) was a 19th Century American lawyer and politician who served as both a United States representative and Senator from Oregon.

Born near Springfield, Illinois, in Sangamon County, Slater attended the local schools.

[1] He resumed the practice of law in La Grande, Oregon and was a member of the State railroad commission from 1889 to 1891.

[1] In 1854 Slater married Elizabeth (Edna) Gray with whom he would father ten children including future Oregon Supreme Court justice Woodson T.

[2] James Harvey Slater died in La Grande in 1899 and was interred in the Masonic Cemetery.