Detailed maps of the sale are handed out at the sale entrance, showing where individual plants by catalog number were located. (This is the 2023 map as a PDF, 122K).
The sale is at the Minnesota State Fair Grandstand. Many plants are outdoors in front of the building, with the tallyers and cashiers back inside. The main sale entrance is through the big Grandstand door at the west end of the building.
Parking for the plant sale is in the big parking lot that's used as the Midway during the State Fair, located to the southwest of the Grandstand.
Accessible parking is located in the Midway parking lot nearest to the Wristband Booth and along Carnes Ave. on the south end of the Garden Fair block.
In case you're not familiar with finding the Grandstand area at the Minnesota State Fair, here's a locator map of the general area: