My annual maps of the NCAA regional groupings are shown below, based on the official tournament bracket. In all cases, the four teams sharing the same color and style (based on the host team's school colors) are in the same regional; the seeded team (with number in parentheses) will host. To increase readability, I've done something new this year. I've created two maps, shown below. You may click on the maps to enlarge them.
The top map shows relatively compact regionals, in which three or four of the teams in a given set are geographically close to each other. As an example of four nearby schools, Tennessee, North Carolina State, James Madison, and Longwood (the latter two from Virginia) are all shown in light orange, with light-blue outline and white letters. As an example of three nearby schools with a distant fourth school, LSU, Louisiana-Lafayette, and Northwestern State are all from the state of Louisiana, with Central Connecticut State joining in (all four schools shown in purple, with yellow letters).
The bottom map shows the more "far-flung" regionals. For example, as shown with black rectangles and yellow letters, the Missouri regional brings in Oregon State and two teams from Long Island, New York, Stony Brook and Hofstra. The Oregon regional (green rectangles with yellow letters) brings in BYU from nearby Utah, but also Wisconsin and North Carolina. Note the distinction between two regions with white rectangles: the Oklahoma region (with maroon outline and letters) and the Nebraska region (with black outline and red letters).
I have a few brief thoughts on the substance of the seedings and regional assignments. Texas's No. 4 seed is a little higher than the Longhorns were ranked in recent national polls. Texas has not done much in the tournament in the post-Cat Osterman era, so I'm skeptical that the Horns will perform at a level commensurate with their seeding. As a Michigan alumnus, I'm happy that the Wolverines are a top-8 seed, meaning they would host a super-regional if they advance past the initial round. However, Cal is a very tough team to face in the opening weekend, with star pitcher Jolene Henderson starting to return to form after an injury.