Later, he served in the United States Senate from 1885 until his death in 1893. He served for four years as chairman of the U.S. Senate Committee on Public Buildings and Grounds, and also served on the Naval Committee. He was president and director of the Central Pacific Railroad the entire time he sat in the Senate. He authored several Senate bills that advanced ideas advocated by the People's Party: a bill to foster the creation of worker-owned cooperatives, and a bill to allow the issuance of currency backed by land value instead of only the gold standard. Neither bill made it out of committee. In Washington, DC, he had a residence on Farragut Square near the home of Baron Karl von Struve, Russian minister to the US.