赫特福德郡（英语：Hertfordshire，英文简称：Herts），英国英格兰东部的郡。赫特福德是郡治。以人口计算，代科勒姆是第1大自治市镇（Borough），圣奥尔本斯市和区是第2大自治市镇，第1大（亦是唯一一个）城市；赫默尔亨普斯特德是第1大镇（Town），沃特福德是第2大镇，斯蒂芬尼奇是第3大镇，圣奥尔本斯是第4大镇。

赫特福德郡实际管辖10个非都市区，因为没有包含单一管理区，无论把它看待为名誉郡还是非都市郡，其人口和面积都分别是1,058,600和1,643平方公里。

Hertfordshire (/ˈhɑːrtfərdʃɪər/; abbreviated Herts) is a county in southern England, bordered by Bedfordshire to the north, Cambridgeshire to the north-east, Essex to the east, Buckinghamshire to the west and Greater London to the south.

Four towns have between 50,000 and 100,000 residents: Hemel Hempstead, Stevenage, Watford and St Albans. The county town, Hertford, once the main market town for the medieval agricultural county ranks 13th in population today deriving its name from a hart (stag) and a ford used as the components of the county's coat of arms and flag. Elevations are high for the region in the north and west. These reach over 240m in the western projection around Tring which is in the Chilterns. The county's borders are approximately the watersheds of the Colne and Lea, which flow southwards each accompanied by a canal. Hertfordshire is at the edge of the London Basin and most of its undeveloped land is agricultural and protected as Metropolitan Green Belt. The volume of intact medieval and Tudor buildings surpasses London, in places in well-preserved conservation areas, especially in St Albans which includes some remains of Verulamium, the town where in the third century AD an early recorded British martyrdom took place. Saint Alban, a Romano-British soldier, took the place of a Christian priest and was beheaded on Holywell Hill. His martyr's cross of a yellow saltire on a blue background is reflected in the flag and coat of arms of Hertfordshire.