My great grandfather, Ludwig August Adolph Ehlers, 1854–1942 BIRTH 19 SEP 1854 • Westensee, Rendsburg-Eckernförde, Schleswig-Holstein, Germany Arrived in USA in 1894 in New York. Sailed out of Hamburg on ship 'Dania'. Last known residence was Neumünster, Rendsburg-Eckernförde, Schleswig-Holstein, Germany He might have gone by Louie Ehlers as well. Trying to find birth documents, with parents names on it.
You can find a Census for 1855 on FamilySearch (39481) for - among others - Westensee and Neumünster available.