City of Gervais Government City of Gervais Visit Website 592 4th St PO Box 329 Gervais, OR 97206 (503) 792-4900 503-792-3791 (fax) Hours: Business Hours: Monday through Friday, 8:00 a.m. to 5:00 p.m. About Map About Government - The city has a population of approximately 2520 people. Elevation of the city is 184 feet. Directions Gervais, Oregon in located in the Willamette Valley within Marion County. Gervais is approximately 13 miles north of the state capital, Salem, Oregon.