Petersfield is a market town and civil parish in the East Hampshire district of Hampshire, England. It is 15 miles north of Portsmouth. The town …Petersfield is a market town and civil parish in the East Hampshire district of Hampshire, England. It is 15 miles north of Portsmouth. The town has its own railway station on the Portsmouth Direct line, the mainline rail link connecting Portsmouth and London. Situated below the northern slopes of the South Downs, Petersfield lies wholly within the South Downs National Park.