The Stonehenge Tour Company runs daily tours from London, focusing on the monument and history of the area. Tour groups are restricted to 16 people each, with hotel pickup and travel in a Mercedes minibus. A number of tour itineraries are available which pair Stonehenge with different sites linked to the legend of King Arthur, history of England and Roman settlement of England. The company also offers private tours during the times of year when tourists are allowed to enter the monument area and touch the stones.
http://www.stonehengetours.com
Premium Tours offers nine tours of Stonehenge with additional stops along the way. Packages include stops at Windsor Castle, Bath and Stratford-Upon-Avon. The Stonehenge Direct tour includes admission to the grounds with an extended afternoon tour of the site.
UK: +44 020 7713 1311
http://www.premiumtours.co.uk/tours/?iDestinationID=2
Viator is an American-operated tour company offering tours internationally. There are two Stonehenge tours offered by Viator--a day trip starting from London and stopping at Windsor Castle, Bath and the monument, as well as a morning or sunset private viewing inside of the monument. Tours pick up at select hotels in London.
USA: (866) 648-5873
International: +1 (702) 648-5873
http://www.viator.com/London/Stonehenge-Tours/d737-spoi
The international tour company Gray Line offers more than a dozen tours with stops at Stonehenge. Excursions include visits to Bath, Salisbury and/or Windsor Castle. One of the company's most popular trips is a road tour of London's most famous monuments--including Big Ben and Parliament--and a stop at the Tower of London, before heading to Stonehenge and Bath. Gray Line tours pick up from a central location and not individual hotels.
US: 800-966-8125
UK: +44 020 7233 7030
http://www.grayline.com/Grayline/destinations/europe/london.go?mode=activities&cat=Gray+Line+Tour
