Find the Monument Trail near the Gold Discovery Museum to head by foot to the James Marshall Monument, which stands on a hilltop overlooking the Coloma Valley. The trail is short (about a half mile), but steep, and ends at the monument and grave where a statue of James Marshall points to the location where gold was discovery January 24th, 1848.
If you'd like a longer hike, continue onto the Monroe Ridge trail. You can make the Monument Trail a loop by walking down High Street, passing Marshall's cabin, the Noteware-Thomas House, and Jail Ruins.