While China has the largest population of Hmong people, an exact figure is hard to determine. According to the 1990 census, of the 7.4 million Miao people, 5.4 million were recorded as speaking a Miao language. Of these, around 2 million spoke a dialect of the Hmong language. Currently, based on projected growth rates, along with the inclusion of previously overlooked dialects, the number of speakers of the Hmong language in China has been estimated to be around 2.8 million.

Many Hmong/Mong war refugees resettled in the United States after the Vietnam War. Beginning in December 1975, the first Hmong/Mong refugees arrived in the U.S., mainly from refugee camps in Thailand; however, only 3,466 were granted asylum at this time under the Refugee Assistance Act of 1975. In May 1976, another 11,000 were allowed to enter the United States, and by 1978 some 30,000 Hmong/Mong people had immigrated. This first wave was made up predominantly of men directly associated with General Vang Pao's secret army. It was not until the passage of the Refugee Act of 1980 that families were able to come in the U.S., becoming the second-wave of Hmong/Mong immigrants. Today, approximately 270,000 Hmong/Mong people reside in the United States, the majority of whom live in California (65,095 according to the 2000 U.S. census), Minnesota (41,800), and Wisconsin (33,791). Fresno, California; Eureka, California; Stockton, California; Sacramento, California; Minneapolis-Saint Paul, Minnesota; Lowell, Massachusetts; Madison, Wisconsin; Milwaukee, Wisconsin; and Wausau, Wisconsin have especially high concentrations of Hmong/Mong people.