Drumcroon is a townland.
Townlands are unique to Ireland. It has more than 60,000 and they are traditional Gaelic land divisions which pre-date the Norman invasion in the 12th century. A townland is the smallest administrative area of land in Ireland. They can vary in size from 1 acre up to 5000 acres, though most are between 50 and 500 acres. The whole country is divided into an invisible network of townlands. Many are rural, and there is not necessarily any town in a townland. Indeed some have no-one living in them at all, eg mountain tops and uninhabited islands. They were used as the basis of leases in the estate system, and subsequently to assess valuations and tithes in the eighteenth and nineteenth centuries.
Some townlands have been forgotten, some survive only on property deeds and other have given their names to towns and districts.
In rural areas there were no street names or house numbers (that is still the case in some parts) and your townland was sufficient to identify you or get a letter delivered. The postman, and anyone else who mattered, knew exactly where in the townland everyone lived. They survive today as important markers of local identity. (A townland is not the same as a US township).
A group of townlands makes a parish and a group of parishes makes a barony.
Drumcroon is 447 acres. In the 1901 census there were 74 people living in it, in a total of 17 houses across the townland. Most were engaged in farming or agriculture generally. http://www.census.nationalarchives.ie/pages/1901/Londonderry/Drumcroon/Drumcroon/
Placenames NI site:
PRONI (the public record office) has attendance records for 7 schools in Macosquin parish. The records themselves are not on-line and so a personal visit is required to view them.