Longoe Farm is situated on the exposed but picturesque shores of the Pentland Firth, and is linked to the Castle by a cliff-top track and strip of rough grazing. It has the debatable advantage of being one of the most northerly farms on the British mainland, with unparalleled views across to Hoy and the Orkneys. Just to the west lies Dunnet Head, the very northernmost point on the mainland.
Over the years, more land has been bought to bring it to its current size of approximately 100 hectares. A further 34 hectares of rough grazing / hill land is also rented. The soil type is a good heavy loam. In the interests of self-sufficiency, 17 hectares of barley and oats are grown, three hectares of turnips and kale, and 25 hectares of grass are cut for wrapped silage and some hay.
Winters can be long in Caithness with cattle being housed from the end of October until the third week of May to avoid cutting up the heavy land. The average annual rainfall is 30 inches (76 cm) which falls fairly evenly throughout the year, though recent summers have been both unusually hot and dry. Due to the coastal position of the farm, snow and frosts are not a big problem, but there can be constant exposure to cruel northerly winds, at times seemingly all the way from Iceland. These winds can salt blast the fresh growth of grass, flatten a promising crop of barley, and sculpt what few trees that survive to a permanent 45 degrees list. Cold sea mists known as haar can be a problem in the summer, slowing growth and stopping hay-making, even when it is hot and sunny half a mile inland. However, despite the short growing season, Caithness is a good livestock rearing area with very few health problems.
Over a number of years, the farm stock have enjoyed success in the show and sale rings due to the dedication, skills, enthusiasm and stockmanship of the McCarthy family, who have looked after the farm since 1967. They form a unique team. However, nothing could have been achieved without the continued keen interest, understanding and encouragement of Her Majesty Queen Elizabeth The Queen Mother over the years. Although Her Majesty handed everything over to her Trust, she continued until her death to take a great interest in her farm and its pedigree livestock.
HRH The Prince Charles, Duke of Rothesay, has shown great commitment to furthering the Trust objectives and visits at least once each year, renting the Castle for a few days in August.