The Memorial Museum of Writer Šatrijos Ragana is a branch of the Mažeikiai Museum. It houses a memorial exhibition about the eminent writer Marija Pečkauskaitė (1877–1930), best known by her pen name, Šatrijos Ragana. It presents the writer's life, her family, the environment and inspirations that surrounded her. On display are the writer's personal belongings: furnishings, household items, documents, study and other notes, and books.

The Pharmacy Museum in Viekšniai is a branch of the Mažeikiai Museum. It is housed in an authentic building from the late 18th century, which still preserves a pharmacy from the second half of the 20th century. The building used to belong to the descendants of the Jewish community in Viekšniai. This is the only museum of a village pharmacy with preserved living quarters of the pharmacist families in Lithuania.

The museum's collection consists of personal objects, furnishings and documents of the apothecaries who worked in the pharmacy and their families, equipment for making medicines, tools, vessels, account books, prescriptions, medicines and pharmaceutical raw materials. Visitors are invited to discover all this in the museum's exhibitions.

The Memorial Exhibition of Professors  Mykolas, Vaclovas and Viktoras Biržiškos, a branch of the Mažeikiai Museum, was established in 2008. The museum is located together with the town library in the reconstructed house of the notable Lithuanian public and cultural figures, the Biržiška family. The exhibition is housed in two rooms. Here visitors can learn more about the brothers Mykolas (1882–1962), Vaclovas (1884–1956) and Viktoras (1886–1964) Biržiškos, their public and creative work, achievements and services to Lithuania. Exhibition panels offer further insight into their parents and the genealogy and life of the Biržiška family.