In the 1870s, he owned nearly 640 acres in the Town of Menomonee (Menomonee Falls today), plus a "half section" (320 acres) in Clay County, S.D.
Thomas was born in County Roscommon, Ireland, on Dec 21, 1816, the third of Patrick and Katherine (Curley) Gill's nine children (five boys and four girls). Both parents lived to the biblical "three score and 10 years" years of age and were buried in Ireland.
Thomas' older brother stayed with his parents and took over the family farm, while the majority of the children migrated to the United States and scattered to the wind.
Thomas had an acceptable education in a common Irish school, then at 25 bid farewell to his parents, home and friends, sailing from Liverpool to New York in 1841 on a three-masted ship that took 38 days to cross the Atlantic.
He began working as a farm hand on Long Island in New York, where he met and married Catherine Curley, daughter of Hugh and Mary Curley, on Jan. 10, 1847. Catherine was born Nov. 25, 1819, also in County Roscommon, Ireland.
The couple traveled to Milwaukee in spring 1847, arriving May 6. They then walked to greater Lannon from Milwaukee, following a route blasted by tree trucks. Thomas purchased 40 acres on Lannon Road and erected a cabin covered with oak shingles he had made with a draw shave tool.
The couple had nine children, six sons and three daughters – Michael, Matthew, James, Mary, Thomas Jr., Henry, Margaret, Andrew and Eugenie – all born in greater Lannon.
Eugenie died at age 15 and is buried as St James Catholic Church Cemetery. The other eight survived to adulthood. Son Matthew became a vast land holder in Clay County, S.D. (the reason Thomas Sr. became a half-section land owner in South Dakota).
In 1870 Thomas Sr., a Democrat, was elected as one of three constables in the Town of Menomonee.
Over the years he expanded his owning fronting Lannon Road from north of Mill Road to south of Lisbon Road as parcels became available.
A prominent piece of his former property is today's Reimer farm and gravel pit at the northeast corner of Mill and Lannon roads, and sections of what became Lannon Park next to the Wanaki Golf Course.
He eventually sold or gave his properties to his children. In his declining years he lived at the family homestead with his son, Matthew, who had returned from South Dakota to take over the original family farm, and his daughter, Mary. In his 80s and early 90s, he continued to walk the length of his former farms until the day he died at 92.
His death came without notice, swiftly, and he passed away without any suffering, according to newspaper accounts. His wife of 49 years, Catherine, had died in 1896. Both are buried in the family plot at St. James Catholic Church Cemetery on Town Line Road, where they joined many other Irish families of the 1830s and '40s from Lannon and eastern Lisbon.
The surviving six sons acted as pallbearers. His two daughters, Mary and Margaret, who had never married, attended the services officiated by the Rev. Paul E. Scheidel, along with many of his 21 grandchildren and three great-grandchildren.