It's the dark blue region in the south eastern region. This is from the year the impeached president Yoon got elected.
Korean politics mirror ours to a degree. The rural/urban divide exists, except for my province. The red area in the north east you see is the super wealthy part of Seoul. It's not much different from the rich assholes in Beverly Hills and Newport Beach voting red with the future billionaires in Bumfuck Arkansas.
My province was a hot bed of resistance against military dictatorship. Under military dictators, the province remained impoverished and that was by design. You probably heard of the Kwangju uprising in 1980. The government deployed troops from rival regions to mow the protesters down.
There are two Nobel Prize winners from South Korea. They both hail from my province. The latest one is Han Kang. She won the 2024 Nobel Prize in Literature.