The website 'House of Names' contains an article entitled 'Penston History, Family Crest & Coat of Arms', which states:

  'The name Penston was brought to England by the Normans when they conquered the country
   in 1066'.

The Normans  identified themselves by reference to the estates from which they came in northern France.  Following the invasion, they continued this practice by taking the names of places they  occupied.

'House of Names' states that the Penston ancestors initially lived in Devon, England. 

The 'Genuki' website references a village in the parish of Gladsmuir, East Lothian, Scotland that is called Penston. The inhabitants of Penston were primarily engaged in the colleries (coal mines). The village of Penston still exists but is essentially a ghost town. 

Included in the Stories section of this website is an item entitled 'History of the Name Penston'. This story includes copies of an article by the House of Names as well as some maps and descriptions of the area near Penston, Scotland.

An interesting tidbit of information is that near the end of the 13th century (in the days of the Scottish hero William Wallace) the village of Penston was  located in the barony of Penston and belonged to William de Balliol, who was the nephew of John  Balliol of Barnard Castle. John Balliol was the father of King John Balliol, who acceded to the  Scottish throne on November 17, 1292. 

You Tube has a video clip entitled 'The Story of a King and a Rebel', which explains the relationship between King John Balliol, William Wallace and English King Edward I (Longshanks). An easy way to view the video is to do a search within You Tube for King John Balliol and the video should appear as one of the selections of the search. A few other videos on King John Balliol are also available from the same search.

A number of members of the original Penston 'family' subsequently moved from Scotland to  England, mostly locating in the area surrounding London. A significant number of 'Irish Penstons' later relocated to Ireland, some future generations emigrated elsewhere and many have  stayed in England.

The eldest Penston documented in this family tree is Alexander (1740 - 1813). He and his wife  Mary Oddy lived in the outskirts of London, England in the district of Surrey.

This family tree traces ten generations of Penstons from Alexander and Mary, including numerous  branches and twigs bearing other surnames.

Research has not been completed on all the generations of Penstons, so a number of 'blanks' are  present in this family tree.

The family tree includes many  surnames other than 'Penston'. As of December 9, 2017 the most  common surnames in the family tree were: Penston (292), McDonald (203), Kastner (190), Armson  (132), Lindsay (128), Warren (93), Smith (83), Ive (73), Ferguson (60), McCrea (67) and  Pellerin (67).