Tamriel Rebuilt is the largest collaborative fan-based modding project for the Elder Scrolls series. It is working to recreate the fictional world of Tamriel on both Morrowind's and Oblivion's engines. This project has existed since before Morrowind's release, though the leadership and members have changed many times since then. Currently, they are completing the province of Morrowind on Morrowind's engine, and Stirk (a small island west of Cyrodiil) on Oblivion's engine.
Originally the Tamriel Rebuilt team had divided mainland Morrowind into six distinct maps, which will be developed separately and sequentially. Maps 1 and 2 were to cover the Telvannis district of mainland Morrowind, Map 3 was to cover the Mournhold district, Map 4 was to cover the Kragenmoor district, Map 5 was to cover the Velothis district, and Map 6 was to cover the Deshaan district.
The first map, called Telvannis, was released in February 2007. A few of the main locations on Telvannis are Port Telvannis, the capital of House Telvanni, Firewatch, the seat of Imperial power in the map, Tel Ouada, Gah Sadrith, Ranyon-Ruhn, and Llothanis. As of December 2008, all quests for this map other than the main quest have currently been released.
The second map, called Antediluvian secrets, was released in December 2008. Some of the important landmarks included the legendary Dwemer ruin of Kemel-Ze, the Telvanni and Imperial settlement of Helnim, as well as the Telvanni settlements of Marog, Alt Bosara, Tel Muthada, and Tel Mothrivra. As of December 2008, this map exists as a beta version only; the player can wander around the map freely, but no quests yet exist.
Due to a re-organization in 2009, the number of six maps was increased to eight, in order to increase productivity and general public accessibility.
The division between the maps corresponds loosely with the areas governed by different Great Houses. The new plan of 8 included the two already developed maps, Maps 1 ('Telvannis') and Map 2 ('Antediluvian Secrets'), both of which cover the regions ruled by the House Telvanni. The remaining maps are planned as follows; Map 3 is centered around the cities of House Indoril and Necrom, and Map 4 contains the remainder of Indoril's holdings including the capital city of Morrowind, Almalexia. Map 5 covers "a bit of every sort of region Morrowind has to offer", including both Imperial and Hlaalu cities, and Map 6 will contain House Redoran holdings in the Véloth Mountains. The final Maps to be released are scheduled to be Map 7, which is centered around the city of Narsis, capital of House Hlaalu, and Map 8 is set to finish the series by concentrating on the stronghold and setting of House Dres.