General aviation pilot reported landing at an airport reportedly closed for UAS operations. After landing the pilot checked for NOTAMS and saw the airport was closed.

Narrative

I flew from ZZZ1 to ZZZ on IFR flight plan in late August. I was cleared to ZZZ by the ground controller at ZZZ1. En route I checked NOTAMS on the Garmin G1000 and saw nothing indicating any alert situation at the airport. I was put on vectors by ZZZ approach as I neared the ZZZ VOR and then handed off to ZZZ1 Approach. As ZZZ1 approach issued a clearance for the visual to land at ZZZ; I cancelled the IFR plan and proceeded VFR. At no point through this--my initial clearance to ZZZ; my check of notams en route; or my clearance for the approach was I notified that the airport had been closed by the authorities for drone operations. I made the usual traffic calls on the CTAF frequency as I flew a normal left downwind pattern for landing. On landing I noticed a car with lights on at the approach end of the runway; but I had remembered seeing a notice the day before indicating that there was work being done at the end of the runway and these lights were consistent with that notice and I landed long. Upon landing I saw several police cars on the property and was notified by an officer that I had just landed at a closed airport. He said a NOTAM had been issued closing the airport and asked if I had seen it. I said; no; and that I had only seen a notice saying (I thought) that there was work being done at the end of the runway; but no notice of closure. He asked if I had checked the FAA site and I said; no; but that i had checked foreflight and the Garmin system on the airplane. I also said that I was on an IFR flight plan; had been cleared to the airport; that I had been cleared for a visual approach; and that I had made radio calls (suggesting of course that no one else knew it was closed either). He said he'd find out what was wrong. I was asked how long before I could take off; got permission to fuel the aircraft and departed about 45 minutes later. I was never told the resolution of the investigation. I did check the NOTAMs when I arrived at my destination and saw that; after I landed; a NOTAM was issued for ZZZ closing the runway. The NOTAM was issued after I landed.Obviously I wished I had questioned more than I had the car at the airport threshold; but I also think that the police should have been monitoring the CTAF for cases such as mine; should have filed a timely NOTAM in the system filed under the ZZZ airport; and also that the police should have alerted ZZZ1 Approach and ZZZ Approach about the closure.