In 1861 President Abraham Lincoln appointed North the official surveyor of the new Territory of Nevada, and North moved to Virginia City, Nevada. The territorial surveyor was a sensitive position in a mining region such as Nevada’s Comstock Lode, where the boundaries of mining claims were the constant subject of lawsuits. Lincoln may have counted on North to keep Nevada Territory loyal to the Union, and to bring Nevada in as a Republican state, as he had Minnesota. North surveyed, invested in silver mining properties, began building an ore-treatment mill he named the Minnesota Mill, and practiced law.