The McLennan County portion of the city is part of the Waco Metropolitan Statistical Area, while the small portion that lies in Coryell County is part of the Killeen–Temple–Fort Hood Metropolitan Statistical Area.

According to the United States Census Bureau, McGregor has a total area of 21.8 square miles (56.4 km2), all land.

[1] The climate in this area is characterized by hot, humid summers and generally mild to cool winters.

McGregor is the site of the former Bluebonnet Ordnance Plant to make munitions during World War II.

[10] SpaceX has a rocket engine development and test facility in McGregor that it acquired from defunct Beal Aerospace.

In May 2016, McGregor passed an ordinance to reduce noise and vibration caused by SpaceX testing activity.

[13] McGregor is the home of Magnolia House, a Victorian property renovated in Season 3 of HGTV's Fixer Upper by Chip and Joanna Gaines.