Flight Crew Instrument; Flight Crew Private
Communication Breakdown; Situational Awareness
ATC Issue All Types; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Incursion Runway; Inflight Event / Encounter Weather / Turbulence
General None Reported / Taken
Human Factors; Procedure
Was on an IFR flight plan to ZZZ; had to divert for an embedded line of thunderstorms with heavy lightning. We were on a west heading to avoid the storm; when we decided to divert to ZZZ1 for passenger comfort. Center cleared us into to ZZZ1 on the visual; during the downwind leg we lost the airport in the low level clouds that pushed in; so we asked to go to ZZZ2 that is 15 miles to the north. ATC cleared us into ZZZ2 on the visual; we stayed on our IFR flight plan and told ATC we would cancel on the ground in case we couldn't make it in. Once we landed I noticed the taxiways were blocked off. I let one of the passengers out that was feeling ill to relieve himself. A construction worker appeared and claimed we landed on a closed runway; I asked him where the X's were on the runway; he claimed they put them in the dirt and weeds off the end of the runway so they did not have to move them when they were seal coating the runway. After my passenger was feeling better we fueled up and taxied out and took off; on climb out I did notice that there was an X about 100 feet off the runway in the grass. We contacted Center and they asked if we were aware that ZZZ2 was closed; I informed them that we figured it out after the fact. ATC then opened up a new IFR flight plan to ZZZ and we continued our flight without any further issues.
GA pilot reported landing at a closed airport after receiving ATC assistance on an IFR clearance.