Debelo Brdo I is located in the City of Gospić, in Lika-Senj County at an elevation of 562 meters above sea level and it covers the area of 3.53 km² (1.36 sq. miles). According to the 2011 census report, there were 60 inhabitants. It is entirely populated by Croats. Nearby places: Debelo Brdo Ii, Smiljan, Novoselo Trnovačko, Podoštra, Trnovac, Kaniža Gospićka, Lički Novi, Žabica, Brušane and Gospić.