The Museum of Bohuslän is the main cultural institution in the province, housed in a building in the centre of Uddevalla. The collections cover the full sweep of Bohuslän history: Bronze Age rock carvings (the best of which are along the coast to the north), Viking-era finds, the medieval and early modern herring trade that made coastal towns like Uddevalla wealthy, and the shipbuilding and fishing industries that dominated until the 20th century.
The natural history section covers the Bohuslän coastline's geology and marine life, including the Ice Age formations that produced the shell banks at Kuröd. If you are spending a day or two in the area, the museum provides good context for everything you'll see along the coast.