It is possible he is a landowner but most of the land in Ireland belonged to the aristocracy, then sub-let to people such as your Captn. in large parcels, these were then sub-let again to the actual person who farmed the lands.
Gentlemen, Esquires and the like would then make a living from the rents.

I notice an Earl of Granard owning a lot of land in the area. You can look up Estates www.landedestates.ie

Griffith Valuation 1854:
William Hill, Parish of Mullingar, Townland of Mullingar, Town of Mullingar Poor Law Union Mullingar tenant of
James Boggs

#22 Blackhall Lane (off Goal St.) a house - no land

John Sullivan, Parish of Piercetown, Townland Rathcogue,Poor Law Union Ballymahon tenant of James Higgins

4a house and garden 1 acre 0 roods 10 perches

Churchtown is both a Parish and a Townland in the Union of Mullingar, also a townland in the Parish of Kilmacnevan.

Griffith Valuation was a tax on property. Carried out by
Richard Griffith who was the director of the project.
You can see how much land by the A.R.P. at the top of a column.
A = acreage; R = Roods; P = perch
An old english form of land measurement, I do know a perch is 18' x 18'
Also outbuildings or offices are listed, if has other assets such as a forge it is listed.

The maps from the GV are quite detailed.

www.failteromhat.com has a list of landowners 1876 and there are no HILL's listed in Westmeath. If a person is a landowner in the Griffith Valuation it would show where
the landlord would normally be listed as IN FEE.

Annette