The “other McPherson family” or “other McPhersons” is a name I conventionally use for the unrelated family of McPhersons who lived in the same areas of Virginia and Tennessee as my McPherson family. Lewis Dwinell McPherson writes,ref
These 2 branches of McPhersons in Rhea county, Tenn. came into each other’s acquaintance there apparently in the 1840s, some 35 years after the arrival of Daniel McPherson's branch in Roane and Rhea counties, Tenn. and to date no report has indicated that either branch ever connected themselves far enough back to indicate anything except a possible common ancestry in Scotland. Neither branch in Tenn. ever recognized the other as kin.
This other branch has been traced back to Daniel McPherson, possibly son of Alexander, who has traditionally been said to have immigrated from Argyllshire, Scotland and settled in Charles County, Maryland. However, researchers have found no evidence to support this claimed Scottish origin, nor even proof that these people were immigrants at all. Widely circulated North American stories about an ancestral “Sandy” McPherson of Argyllshire appear to be mythical.
Later generations of McPhersons seem more likely to confuse the branches.
DNA evidence indicates that the two families are not related in a male line. My McPherson family belongs to R1a, and, while the situation with the other McPherson family is murky, those lines appear to be in haplogroup R1b.
In 2014, I contacted a DNA match who told me her maiden name was MacPherson. Naturally, I assumed we were related through our McPhersons, but it turned out she was descended from the other family, and we were actually related through Jared and Eleanor McDonald.
The two families connected within my immediate ancestry with the marriage of Thomas Hawes McPherson and Amanda Jane McPherson in 1869.ref Thomas was of the other family; Amanda was a daughter of James and Juliet McPherson.