Kollmar is located approximately 13 km west of Elmshorn, directly on the Elbe in the Kremper Marsch.

They constructed Oevelgönne Castle (meaning "envy") in 1586, with the Italian architect Franz de Rocha as the builder.

In 1959, during construction work at the intersection of Strohdeich-Deichreihe-Langenhals roads (coordinates: about 53.751169, 9.473952), remnants of the former castle mound were found, including fragments of masonry and sandstone decorations, as well as cobblestone paving.

Kollmar is a popular destination for day-trippers from surrounding areas who enjoy watching ships pass along the Elbe shore.

[3] A notable sight is the Church of Kollmar from the mid-15th century, a single-naved brick building with a three-sided eastern closure.