Working a single-surname project. The earliest I have is Thomas De Seagrave who entered England with Wm the Conquerer and was granted land in what is not Leicestershire. I have one report that he supplied the name for the village of Seagrave (but there is another story that a descendant took the family name from the village) what is perplexing is that the descendants all spelled the name Segrave (whereas it is actually spelled Seagrave on all maps)!
I have 5000+ names (some are duplicates), 40+ variant spellings. To illustrate the ease with various spellings may occur: The 1900 census of the Chickasaw Nation, Indian Territory lists my G-grandfather (Thomas W.) with the spelling of Seagrove (my G-grandmother Elizabeth (?) was 1/4 Chickasaw. In the 1910 census for the State of Oklahoma, my grandfather James Britton's Surname appears as Segroves. It is interesting to note that all the more than 40 variant spellings I have found are Soundex S261! It's also interesting that a preponderance of those included in the SSN Death Index are shown as Segrove (s).
Another story - this time about Seagrove, NC and Seagraves, TX. Both were supposedly named for a railroad man. In the case of NC city, it is said that he was a man of exaggerated ego, and he painted such large letters on the station sign, that there was no room for the last S. Is it possible that these two were the same man or at least related?