Louis Nagel (July 28, 1818 - August 10, 1870) was a German-American lithographer active in New York and San Francisco in the middle part of the 19th century. Nagel was born in Darmstadt, Germany. It is unclear when he emigrated to the United states, but he was active as a lithographer in New York as early as 1844. He exhibited the American Institute in both 1846 and 1847. He partnered with fellow Darmstadt-born lithographer Adam Weingärtner (1813 - 1883), creating the firm 'Nagel and Weingärtner'. Census records suggest he and his wife shared a residence with Weingärtner and his wife. The firm remained active until 1856, advertising as the only firm in New York to use the lithographic techniques developed by the Parisian Rose-Joseph Lemercier (1803 - 1887). This most likely refers to Lemercier's shading techniques. When the firm broke up, Nagel relocated to California, where he set up shop and continued to produce views and maps, at first independently (1858 - 1861), then in partnership with R. W. Fishbourne and Charles C. Kuchel (1862), then once again independently (1863 - 1865). He died in 1870.