Weimar is an unincorporated community in Placer County, California, located in the Sacramento area. Weimar is located 4.5 miles south-southwest of Colfax. As of 2010, its population is 209. The Weimar post office opened in 1866. An explanation of the town's name comes from the Geisendorfer family; descendants of George Geisendorfer, founder o…Weimar is an unincorporated community in Placer County, California, located in the Sacramento area. Weimar is located 4.5 miles south-southwest of Colfax. As of 2010, its population is 209. The Weimar post office opened in 1866. An explanation of the town's name comes from the Geisendorfer family; descendants of George Geisendorfer, founder of the town. George Geisendorfer was born in the area of Weimar, Germany. Many of the original inhabitants of Weimar were also of German descent. Members of the town, and the Geisendorfer family, have testified that George Geisendorfer himself decided to rename the town “Weimar” when the post office rejected the original name of New England Mills. In April, 1919, in the wake of the end of World War I, a resolution was introduced in the California State Senate to change the town's name to Argonne. The resolution was defeated after the local senator insisted the name was not German, but actually came from Weimah, a chief of the Grass Valley tribe of Southern Paiute Native Americans, who had been hospitable to the area's first white settlers. The senator further stated that postal authorities had misspelled the name.