Pinus nelsonii, Nelson's pinyon, is a species of pine native to the mountains of northeastern Mexico, in Nuevo León, San Luis Potosí and Tamaulipas at 1,800–3,200 m altitude.

The crown is rounded and dense, and resembles that of the unrelated Pinus pinea from the western Mediterranean.

[citation needed] Only recently it has been cultivated outside its native range, grown more for its botanical curiosity than for ornamental values.

Evidence from three nuclear genes (Syring et al., 2005) and cpDNA (Gernandt et al., 2005) resolve P. nelsonii as sister lineage to the remaining members of sect.

In contrast, the LEA-like locus used in this study places P. nelsonii in a unique, moderately supported (71% BS) position sister to sect.