According to The Book of Mormon

Book of Mormon

The Book of Mormon is a sacred text of the Latter Day Saint movement that adherents believe contains writings of ancient prophets who lived on the American continent from approximately 2600 BC to AD 421. It was first published in March 1830 by Joseph Smith, Jr...

, Jashon referred to a land and a city in the land northward near the land of Antum

Land of Antum

According to The Book of Mormon, the land of Antum was in the land Northward and was near the city of Jashon. The prophet Ammaron deposited all the sacred engravings of his people in the Hill Shim which was located in the land of Antum . This verse is the only place in the book where the land Antum...

. Jashon is mentioned in only two verses: . The Nephites retreated before the Lamanites until they reached Jashon. From Jashon, their captain, Mormon

Mormon (prophet)

Mormon is believed by followers of Mormonism to have been the narrator of much of the Book of Mormon, a sacred text of the Latter Day Saint movement, which describes him as a prophet-historian and a member of a tribe of indigenous Americans known as the Nephites...

, went to the land Antum

Land of Antum

According to The Book of Mormon, the land of Antum was in the land Northward and was near the city of Jashon. The prophet Ammaron deposited all the sacred engravings of his people in the Hill Shim which was located in the land of Antum . This verse is the only place in the book where the land Antum...

 to fulfill the promise made in his youth to Ammaron

Ammaron

According to the Book of Mormon, Ammaron was a Nephite record-keeper and perhaps a prophet...

to record a history of his people.