The endangered raptors - which feed on young grouse - have been recorded this year on land that is part of the Denton Hall estate in Wharfedale.
The estate, between Ilkley and Otley, was previously the seat of several prominent Yorkshire families, including the Wyvills of Constable Burton Hall, before it was sold to engineering firm NG Bailey in 1976.
Last year, NG Bailey announced that they would no longer lease out Denton Moor to shoots after a number of suspicious incidents involving wildlife persecution.
A gamekeeper employed by the tenant was convicted of killing a badger in an illegal snare and a marsh harrier was shot at and its nest destroyed in 2017, though no charges were ever brought.
NG Bailey ended the arrangement after stating that these incidents did not reflect the company's ethics and values.
This week they confirmed that hen harriers had been spotted on the moor again following a period of sympathetic landscape management.
An estate spokesman said: "It’s fantastic to see that a number of hen harriers have established a roost on our estate. We take our responsibilities for the moorland very seriously and ensure it is managed respectfully, maintaining an exceptional habitat for all wildlife and plants.”
Peatland habitat on the moor is also starting to regenerate, with the expansion of important plant life such as sphagnum moss.
Healthy peatlands are crucial for locking carbon into the ground to tackle climate change, creating rich biodiversity and reducing flood risk in the valley below by holding back large amounts of water.
Ban Bloodsports on Yorkshire's Moors spokesman Luke Steele added: "The sight of hen harriers returning to roost is an amazing natural spectacle that must be protected for future generations to experience. It’s fantastic to see these magnificent birds of prey choosing Denton Moor to make their home.
“NG Bailey’s conservation drive to restore the hen harrier population in Wharfedale is not only commendable, but represents a symbol of hope for threatened wildlife everywhere.”