Flight Crew Flight Instructor; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 65; Flight Crew Total 4199; Flight Crew Type 5
Situational Awareness
Deviation / Discrepancy - Procedural Clearance; Ground Incursion Runway
Flight Crew Became Reoriented
Airport; Human Factors
My student and I landed at CNW for a training flight. We exited RWY 17L and was told by the tower to taxi back to and hold short of runway 17R at taxiway hotel. We taxied via the ramp to what I thought was a taxiway that parallels a grass triangle between the ramp and 17R. I expected to see taxiway markings as we entered what I thought was taxiway delta only to realize that they were in fact hold short markings. The ramp at CNW is rather large and we did not realize the hold short markings were there due to the curvature of the ramp and line of sight.  They are also not depicted on the airport diagram. We exited the area as quickly as we could and continued our taxi to RWY 17R at Hotel. Ground never said anything to us about it nor did we receive a brasher warning. We departed CNW and returned to our base airport.Contributing factors: the hold short area was not depicted on the airport diagram. There was so signage nearby to indicate the hold short line. The hold short markings did not parallel or follow the active runway and as a result we didn't expect to see them there. I brought up the subject at our last aviation safety meeting; but no one from CNW was in attendance. I intend to continue to follow up on the matter.
Beech 19 flight instructor reported being cleared to taxi to Runway 17R and hold short of Taxiway Hotel after landing Runway 17L at CNW. Runway 17R was formerly a taxiway and a very long hold line runs along its west side which was inadvertently crossed approaching Hotel.