Sh2-161 is a bright emission nebula located in the constellation of Cassiopeia. It is part of a larger complex of star-forming regions and is known for its striking appearance, which is primarily due to the ionization of gas by nearby hot stars. The nebula is approximately 10,000 light-years away from Earth and spans several light-years in diameter. This nebula is often studied by astronomers to understand the processes of star formation and the interactions between stars and their surrounding gas. Sh2-161 contains several young stars that contribute to its luminosity, making it an interesting target for both amateur and professional astronomers.