"The American Indian Experience (AIE) offers access to an online library, featuring more than 150 volumes of scholarship and reference content, hundreds of primary documents, and thousands of images."

"The first-ever database dedicated to the history and culture of Latinos. The Latino American Experience includes over 200 volumes of reference and scholarly titles"

"The African American Experience is a wide ranging online collection of material on African American life, drawing on information from 300 titles covering all aspects of the African American experience."

"...provides free public access to digital collections of significant primary and secondary resources on water in the western United States."

"...a central search portal for digital collections about the Mountain West region. We provide free access to over 700,000 resources from universities, colleges, public libraries, museums, historical societies, and government agencies, counties, and municipalities in Utah, Nevada, and other parts of the U.S. West."

Lots of stuff, including digitized runs of pre-1923 journals.

California-centric

"Heritage West is a database that brings together thousands of digital objects from the collections of museums, libraries, historical societies and archives from throughout the Western United States. Included in this database are photos, documents, artifacts, costumes, diaries, oral histories and manuscripts representing the West's cultural, scientific and historic heritage."