Richthofen Castle, Gothic Revival mansion in Montclair, Denver, United States.

Richthofen Castle is a 35-room Gothic Revival mansion of rough grey stone with half-timbered upper walls in dark brown wood and light infill. A square tower with a steep pyramidal roof and finial stands at the left, beside a gabled roof over an arched stone entryway with a small conical-roofed porch. Tall chimneys and a grey stone chimney stack rise above the roofline; windows are grouped and multi-paned.

Baron Walter von Richthofen, a German immigrant from the Richthofen family, had the mansion completed in 1887 to designs by Denver architect Alexander Cazin. He laid out an ornamental garden around it so his wife would not feel isolated in the countryside. Maurice Biscoe and Henry Hewitt made additions and remodels in 1903, and Jules Jacques Benedict followed in 1910. By the mid-20th century developers had surrounded the castle with a new neighbourhood of Victorian-style houses.

Walter von Richthofen laid out an ornamental garden around the house so his wife would not feel isolated in what was then open country outside Denver. In 1984 a bar opened in the mansion named for his nephew Manfred von Richthofen, the First World War fighter pilot known as the Red Baron.

Richthofen Castle stands at 12th Avenue and Olive Street in Montclair, Denver, and is a private residence, so visitors view it only from the public street. The grey stone tower and half-timbered upper walls are best seen from the sidewalk on Olive Street. The grounds are not open to the public.

Walter von Richthofen's nephew was Manfred von Richthofen, the World War I fighter pilot known as the Red Baron. In 1984 a bar named in the pilot's memory opened at the castle, a link between the Denver mansion and the German airman.