In 1857, he and his brother James McMillan Shafter won a legal battle after which their client sold them the contested property of Point Reyes.

His brother, James McMillan Shafter, also attended Wesleyan University, and graduated from Yale Law School.

[7][8][9] In 1857, a complex real estate litigation resulted in Shafter winning a victory for his client, Dr. Robert McMillan, of a large tract of land at Point Reyes in Marin County.

[7] In turn, they leased land to dairy farmers who provided milk and butter to an ever-growing San Francisco and prospered.

[12] The families of Oscar and James Shafter owned large portions of Point Reyes from 1857 to 1919, when the land was sold in parcels.

[16] Shafter was again a candidate for U.S. Senate in the 1873 special and regular Senatorial elections, but lost to Democrat John S. Hager and Anti-Monopolist Newton Booth, respectively.

Shafter married Sarah Riddle in Wilmington, Vermont, in 1840 and the couple had eleven children: ten daughters and one son.