[4] Obregonia denegrii typically grows as a single plant, characterized by a sunken and woolly apex.

The areoles exhibit 2 to 4 whitish to brown spines, measuring approximately 5 to 15 mm (0.20 to 0.59 in) in length, on the young tubercles.

In the summer, flowers bloom, emerging between the wool of the apex and at the center of the stem on young tubercles.

The external perianth segments exhibit a greyish hue, and the pericarpel is either exposed or possesses a few scales.

[5] Obregonia denegrii originates from the Valley of Jaumave in Ciudad Victoria, Tamaulipas, Mexico, commonly thriving at elevations around 1000 meters.