Everybody wants to believe their Penn ancestors are directly connected to William Penn of Pennsylvania, and in some cases this leads to Insane Troll Logic. One website that *CLAIMS* (bwahahahahahahahaha, excuse me) to have done "a lot of research" has a "William Penn born 1609 in Plymouth, Massachusetts" (bwahahahahahahaha, that's 11 years before the Mayflower!), who "moved to" Westmoreland County, VA (more likely emigrated directly there in the first place) yada yada yada....
By the way, don't let anybody tell you that "Penn" is a "Welsh" name. It's not, or not exclusively. It's *Cornish*, along with "Tre-" and "Pol-". ("By Tre, Pol, and Pen, Shall ye know all Cornishmen").
Anyway, I was trying to sort out the John Penn who married Elizabeth Penn of Anne Arundel (somebody has him also mis-married to Elizabeth Penn (Elizabeth Waters) of Somerset County, MD), and before very long I just had to give up. The dates were impossibly, terribly tangled because someone had jammed several different Penn families together with no rhyme or reason - mostly trying to force connections to THE William Penn.
I found references to a William Pen (age 26), who sailed for Virginia on the "Merchant's Hope" in 1635, and to a William Penn of Birmingham, Warwick, who took ship for Salem in 1630 with the "Winthrop" fleet (he disembarked in Charlestown) - a James and Katherine Penn, probably husband and wife, made the same voyage and got off at Boston. I do *not* think the two Williams were the same person.
Other Penns who headed for the New World before The William included Christan(sic) Penn, who came to Plymouth on the "Anne" in 1623 with the Oldham family; Francis Penn (age 22), embarked for St. Kitts on the "Mathew" in 1635; and Robert Penn, who somehow survived the hell-ship "Abigaile" to Virginia in 1620 (he was listed among the servants to Capt. Samuel Mathews at James City in 1624/5; he was then 22).
There was a knot of Penns in Anne Arundel County, MD, in the late 17th-early 18th century, and they *don't* seem to have come up from Virginia by way of Somerset County (no Penns there). It's unclear whether they came up the *west* side of the Chesapeake Bay, or filtered south from Pennsylvania, or what. Of course they've been claimed as relatives of The William Penn, but evidence for that is scanty at best.