Da-Yuan dayitong zhi 大元大一統志 or Yuan yitong zhi 元一統志 is the imperial geography of the Yuan dynasty 元 (1279-1368).
A description of the whole empire was an important and desirable task for each greater dynasty in China. Tang 唐 and Song 宋 emperors had already fulfilled this task, and on the basis of works like Yuanhe junxian tuzhi 元和郡縣圖志 (Tang), Taiping huanyu ji 太平寰宇記 (Song) and Yudi jisheng 輿地紀勝 (Song), the Yuan emperor Qubilai (posthumously Yuan Shizu 元世祖, r. 1260-1294) had an imperial geography compiled for the Yuan empire.
In 1293 a first version in 755 juan was finished, compiled under the guidance of the astonomer and cartographer Jamāl al-Dīn (d. 1301; Chinese transcription "Zhamalading 札馬剌丁") and Yu Yinglong 虞應龍. In 1303 "Beilanxi 孛蘭盻" and Yue Xuan 岳鉉 started working at the final edition which incorporated the information other geographical works like Yunnan tuzhi 雲南圖志 and Liaoyang tuzhi 遼陽圖志, resulting in a 1,300-juan long version in 600 volumes (ce 冊).
The imperial geography of the Yuan is the largest geographical description of any Chinese empire, but unfortunately only fragments of 44 juan are preserved (including the preface by Xu Youren 許有任). Nevertheless it can be assumed that a great part of its content was adopted by later geographies, like the Da-Ming yitong zhi 大明一統志 and many local geographies and provincial gazeteers (e.g. Manzhou yuanliu kao 滿州源流考, Rehe zhi 熱河志, Menggu youmu ji 蒙古游牧記, Rixia jiuwen kao 日下舊聞考).
Zhao Wanli's 趙萬里 reconstruction of the Yuan imperial geography, Yuan yitong zhi 元一統志 (Beijing: Zhonghua shuju, 1966), has a length of 10 juan.