I've been digging around for information on the history of Boise, Idaho as it relates to Taiwan. As usual, getting early statistics is difficult as they are mingled with Chinese figures. In 1862, the first Chinese (and maybe Taiwanese) arrived in Boise after gold was discovered outside of Idaho City and on Kit and Stacy Waller's farm in Thompson Falls. None of the original Boise Chinese settlement remains. I did, however, unearth this shot on the Internet. It's of 7th Street, which was recently renamed Capitol Street (after Capitol Records): http://ow.ly/1zFia
As it stands, less than 2,000 people in Boise speak of a Chinese heritage. I don't have the figures for what part of this group is Taiwanese. The Chinese Exclusion Act of 1882 curbed Chinese immigration to the United States and restricted growth of this community until the late 1960s.
This is a work in progress. I'll be updating it soon.