The Samogitian Museum Alka is the essential stop in Telšiai. It explains why the town matters: not as a pretty provincial centre alone, but as the cultural capital of Žemaitija, the Samogitian region that has long kept a separate identity inside Lithuania.
Expect archaeology, folk art, estate archives, religious pieces, and paintings rather than a single blockbuster object. The museum is strongest when it shows the texture of rural and noble Samogitian life, and it gives useful context before you walk the old town.