Loomis was a local homesteader and photographer who documented the 1915 eruptions of Lassen Peak, and was instrumental in the 1916 establishment of the national park.

In 1929 Loomis donated the museum and 40 acres (16 ha) of surrounding lands to the National Park Service, which since then has used the structure as an interpretational facility.

[2][3] The Loomis Museum is a one-story rectangular building built of local volcanic rock in cut-face random ashlar coursing.

[3] Described in 1952 as "ugly quasi-Spanish", the Loomis Museum was briefly considered for demolition and replacement during the Mission 66 program.

[3] The museum and seismograph building are also part of the Manzanita Lake Naturalist's Services Historic District.