you need to search for bmds on 
https://www.irishgenealogy.ie/en/ bothe church and state
I started with 1823-1837 Tithes Applotment Books based upon the index work of the Irish Genealogy Hub’ see 
http://www.irishgenealogyhub.com/derry/tithe-applotments/desertmartin-parish.php   The relevant original books are in the Public Record Office of Northern Ireland (PRONI) Belfast
re arranging by townland my guess is Anagh is for later spelling Annagh
McCristal, Arthur   Townland: Anagh Year: 1827
McCristal, Michl.   Townland: Anagh Year: 1827
McCristal, Daniel   Townland: Cranny Year: 1827
McCristal, Widow    Townland: Cranny Year: 1827
McCristal, Bryan   Townland: Luney Year: 1827
McCristal, Jas.      Townland: Luney Year: 1827
McCristal, Thos., Jr.   Townland: Tirgan Year: 1827
McCristal, Thos., Sr.   Townland: Tirgan Year: 1827
using one spelling only and arranging by civil parish I start with
1859 Griffiths valuation three sources 
1. 
https://www.failteromhat.com for quick index.   
Mc Crystal   James   Curr         Desertmartin   Derry
Mc Crystal   James   Desertmartin      Desertmartin   Derry
Mc Crystal   Michael Annagh and Moneysterlin   Desertmartin   Derry
Mc Crystal   Henry   Brackaghlislea   Kilcronaghan   Derry
Mc Crystal   Anne   Drumsamney      Kilcronaghan   Derry
Mc Crystal   Philip   Drummuck      Maghera   Derry
2. 
http://www.askaboutireland.ie/griffith-valuation/ for detail and map ref ..  3. 
https://www.nidirect.gov.uk/information-and-services/search-archives-online/valuation-revision-books since 1859
Mc Crystal   James   Curr         Desertmartin   Derry
map ref 3 A,B
Mc Crystal   James   Desertmartin      Desertmartin   Derry
map ref 22 18
Mc Crystal   Michael Annagh and Moneysterlin   Desertmartin   Derry
map ref 21 10 acres and house valued at 5 shillings pa
with patience you should be able to look this homestead up plot 21 runs SW to NE divided up by roads part of one exists today 
switching to google modern map the lane , is the second lane branching off eastwards from the A 29 tobermore Rd , north of  Knocknagin school the first lane sweeps around to nearly join up with the first.  roughly the address is 77 Tobermore road, desertmartin BT45 5LF
switching to satellite view its currently redeveloped you can judge where the Mccrystal home was or is.
3. 
https://www.nidirect.gov.uk/information-and-services/search-archives-online/valuation-revision-books since 1859, wil alllow you to find when that Michael left the property after 1859
hoping some of this is new to you
ps when useingbmd search as at top, use all spellings possible woops see  how many 
https://www.johngrenham.com/findasurname.php?surname=mccristal