The railroads in the western United States were primarily built by the ethnic group

- Germans

- Chinese

- Spanish

- English

Answer: Chinese after a job ad resulted in only a few hundred responses from white laborers.

Chinese workers building a cut and a bank at Sailor's Spur in the Sierra foothills for the Central Pacific Railroad in California, 1866.

Chinese workers building a cut and a bank at Sailor's Spur in the Sierra foothills for the Central Pacific Railroad in California, 1866.