Thomas Eyre was an Irish military engineer

Military engineer

In military science, engineering refers to the practice of designing, building, maintaining and dismantling military works, including offensive, defensive and logistical structures, to shape the physical operating environment in war...

.

Thomas Eyre was the second son of Colonel Samuel Eyre of Eyreville, County Galway

County Galway

County Galway is a county in Ireland. It is located in the West Region and is also part of the province of Connacht. It is named after the city of Galway. Galway County Council is the local authority for the county. There are several strongly Irish-speaking areas in the west of the county...

. In 1738 he joined the regiment of James Oglethorpe

James Oglethorpe

James Edward Oglethorpe was a British general, member of Parliament, philanthropist, and founder of the colony of Georgia...

, the founder of the Colony of Georgia, and sailed to the colony. He rose from the rank of cadet to be sub-engineer for Georgia and South Carolina

Province of South Carolina

The South Carolina Colony, or Province of South Carolina, was originally part of the Province of Carolina, which was chartered in 1663. The colony later became the U.S. state of South Carolina....

 by 1743, when he left for England. As a lieutenant, Eyre joined Trelawney's Regiment of Foot, headed by Edward Trelawney, Governor of Jamaica. He served in Jamaica

Jamaica

Jamaica is an island nation of the Greater Antilles, in length, up to in width and 10,990 square kilometres in area. It is situated in the Caribbean Sea, about south of Cuba, and west of Hispaniola, the island harbouring the nation-states Haiti and the Dominican Republic...

 and at Roatán

Roatán

Roatán, located between the islands of Útila and Guanaja, is the largest of Honduras' Bay Islands. The island was formerly known as Ruatan and Rattan...

 (Rattan), and was promoted to captain in 1748. Eyre retired from active duty in 1752.

On 31 August 1752, Eyre was appointed Surveyor General of Ireland

Surveyor General of Ireland

The office of Surveyor General of Ireland was an appointed office under the Dublin Castle administration of Ireland in the 17th and 18th centuries. The Surveyor General was typically responsible for the surveying, design and construction of civic works, and was often involved in overseeing the...

, having purchased the office from Arthur Jones-Nevill. He undertook works at the Royal Barracks

Collins Barracks (Dublin)

Collins Barracks is a former military barracks in the Arbour Hill area of Dublin, Ireland. The buildings are now the National Museum of Ireland, Decorative Arts and History...

 in Dublin, but the condition of the barracks was criticised by the Commissioners of the Ordnance for Ireland. As Surveyor General, he was also involved in harbour works at Dun Laoghaire

Dún Laoghaire

Dún Laoghaire or Dún Laoire , sometimes anglicised as "Dunleary" , is a suburban seaside town in County Dublin, Ireland, about twelve kilometres south of Dublin city centre. It is the county town of Dun Laoghaire-Rathdown County and a major port of entry from Great Britain...

, and was responsible for the rebuilding of the State Apartments at Dublin Castle

Dublin Castle

Dublin Castle off Dame Street, Dublin, Ireland, was until 1922 the fortified seat of British rule in Ireland, and is now a major Irish government complex. Most of it dates from the 18th century, though a castle has stood on the site since the days of King John, the first Lord of Ireland...

. In 1763, the office of Surveyor General was abolished, and Eyre was transferred to the new post of Chief Engineer of the Ordnance.