The heart of Basque culture in the USA is Boise, Idaho, which has the country’s largest Basque population and even a Basque-speaking mayor, David Bieter. The Basque heritage is reflected in this painting (from Wikimedia) where the B has the colours of the Basque flag:
Another Basque mural in Boise is described at the blog Boise Basque Tour. The Basque painter Judas Arrieta recently created a mural at a local hotel in Boise, which is reported about at the web page Euskal Kultura. The city also has a Basque cultural centre (euskal etxea – see this link for a complete list of all the Basque cultural centres in the world).
The University of Nevada, Reno, with its Center for Basque Studies, is one of the few universities outside of the Basque Country that conducts research and teaching in Basque language and culture. Nevada also holds a Basque mural, made by Beverly Caputo in Gardnerville, also reported about by Euskal Kultura.
And lastly, one can also mention Bernardo Atxaga‘s novel Soinujolearen semea as another Basque-US connection, since it partly takes place in California. In Margaret Jull Costa’s English translation it’s called The Accordionist’s Son.