The Second LHAASO Collaboration Conference in 2026 & The Academic Symposium for the 10th Anniversary of the LHAASO collaboration

We study the high-Galactic-latitude ultra-high-energy gamma-ray source J0956+4622 with LHAASO WCDA and KM2A. At a Galactic latitude of 50.8°, it is currently the only LHAASO source above 100 TeV with latitude greater than 20°. The source is extended, shows no clear variability, and has a spectral peak at 72.2 TeV, the third highest among LHAASO sources. No firm pulsar or 4FGL counterpart is found, while the emission partly overlaps neutral hydrogen; both hadronic and leptonic models can describe the spectrum. In addition, using the Crab Nebula as a reference, we present a preliminary study of the atmospheric systematic uncertainty of KM2A.