The ADAMSON surname may or may not be connected to the ADAMS surname.  My research on the ADAMSON name goes back over 700 years to Scotland and Northern England.  I have not found any connection to the ADAMS surname. An England researcher has researched the topic in depth and he has found no connection. There may be some connection to other Clans such as, MACKINTOSH but any connection would go back to pre 1200..  Of all my research on the ADAMSON name, I know of no ADAMSON in the USA that is connected to the ADAMS surname in any way except by marriage.

I have read Adamson Lineage’s from England, Scotland, Australia, and New Zealand and have seen No references to the ADAMS name.

I quote the research of  Mr. G.F.S. Adamson of Edinburgh, Scotland.

“The name ADAMSON is quite old one, indeed Cain and Abel were Adams sons! Adam in Scotland is derived from the gaelic word adahm meaning red as it does in Hebrew.” “ They were, the red haired ones.” “The first official written record of a family is contained in the Chatlary of Dunfarmline in the fourteenth year of the reign of King Robert Bruce.  Letters patent to the Freeman ADAMSON “Libertas Adami Filh Adami coram justitario nostro  etc.” “ this was in Aberdeen on the tenth, September 1320 and applied to ADAMSON and his sons Robert, John, Reginald and Duncan.”
“ I think it is accepted the main Scottish family is descended from one of the two grandsons of Shaw Mor, who captained Clan Chattan at the battle of the Inch at Perth.”  Shaw Mor died in 1405 and is buried at Rothiemrcus.  His son James, who was killed at the Battle of Harlaw in 1411, had two sons.  Ciar (the brown haired one) and Adahm (the red haired one). Their territory was in Badenoch at he Shaw stronghold of Loch an Eilean Castle, the ruin still stands today……………” END OF QUOTED MATERIALS