Molly Miller, who is retiring from the trade, has operated the building as a country house hotel for 33 years.
The grade-2 listed property at Northop in Flintshire went for the asking price, according to agent Colliers International. The Georgian property was bought by Richard and Lorraine Earl of Milton Keynes, who will continue to run it as a hotel.
Highfield Hall is set in extensive gardens and features 10 bedrooms including a bridal suite, a dining room for 20 people, a main dining room seating 60 people and conservatory seating 50 people. There is also large function room with room for 150 people.
Neil Thomson, associate director of hotels at Colliers International in Manchester, secured the sale. He said: "We have sold more than 80 hotels and guest houses in 2012 alone, demonstrating growing interest from prospective buyers in the licence and hospitality sector.
"We are speaking to an increasing number of buyers looking to make a lifestyle change and Highfield Hotel represented a fantastic opportunity for an owner operator to acquire a ready-made business with an excellent reputation."