A MAJOR orienteering event will be held in the Highlands this Sunday.

Round 13 of the NSW Orienteering State League will be conducted in Belanglo State Forest.

The competition is open to orienteering participants of all ages and abilities.

Competitor ages range from nine to people in their 80s.

It is set to be a big weekend for NSW Orienteering.

Round 12 of the league will be held in Appin this Saturday.

NSW Orienteering marketing and communications officer Ian Jessup said the state league was the main winter orienteering bush competition in NSW.

Jessup said orienteering involved participants using a map to run or walk to checkpoints.

He said checkpoints on the map course must be completed in the correct order.

Jessup said for the more advanced courses, a compass was necessary for participants.

"Orienteering is 50 per cent academic, 50 per cent physical."

Sunday will mark the final round of the 2015 NSW Orienteering State League.

Jessup said preparations were on track for the event in Belanglo State Forest.

"We have 178 people with pre-entry for this weekend and I expect another 20 people to rock up on the day," he said.

Jessup said orienteering had been held in Belanglo forest for more than 30 years.

He said Highlanders wishing to try orienteering could head along on Sunday at 9.45am to register.

* For more information, visit www.onsw.asn.au