Riamsalio Phetchareun at the Southeast Asian Resource Action Center in Washington D.C. recently posted a quick breakdown by state of Southeast Asian populations in the US based on the Census 2010 results.
Hopefully we'll soon see an update that's as useful as their statistical profile regarding the Census 2000.
For the Lao community, the largest states remain California, Texas, Minnesota and Washington. For the Hmong it's California, Minnesota, Wisconsin and North Carolina.
SEARAC is a national organization that advances the interests of Cambodian, Laotian, and Vietnamese Americans by empowering communities through advocacy, leadership development, and capacity building to create a socially just and equitable society. You can visit them at www.searac.org