Jaen, officially the Municipality of Jaen is a 2nd class municipality in the province of Nueva Ecija, Philippines. According to the 2020 census, it has a population of 79,189 people.

Nueva Ecija, officially the Province of Nueva Ecija, is a landlocked province in the Philippines located in the Central Luzon region. Its capital is the city of Palayan, while Cabanatuan, its former capital, is the largest local government unit (LGU). Nueva Ecija borders, from the south clockwise, Bulacan, Pampanga, Tarlac, Pangasinan, Nueva Vizcaya and Aurora. The province is nationally known as the Rice Granary of the Philippines, producing the largest rice yield in the country.