It is grown in France, particularly Alsace, and the U.S. In the U.S., many of the vines called Pinot Blanc are actually a related variety, Melon de Bourgogne/Muscadet, that has the same parents as Chardonnay. This mistake was discovered around the mid 1980s, and now Pinot Blanc purchased from a nursery will be the genuine article.
Pinot Blanc has also been confused with Chardonnay, and wineries often vinify it in a similar style, using barrel fermentation, new oak and malolactic fermentation. It can also be treated more lightly and made into a crisper wine that still has some ability to age.