Season 2: Episode 25: E Peterbus Unum
When Peter tries to get a permit to build a swimming pool in his back yard, he finds out that his lot is actually not part of Quahog, and therefore not part of the U.S., so he forms his own country of Petoria. When Peter gets no respect in the U.N., he decides to invade his neighbor's pool, which brings the U.S. Army to his border. The Griffins can only survive so long with no water, electricity, heat, or access to the United States, and finally, Lois and the kids leave President Peter to his third-world country. Peter finally repatriates only a week after seceding.