Groundwork Caerphilly will take ownership of Ty Mynyddislwyn from Caerphilly County Borough Council and run a host of community activities in the building.
The charity will run sessions on employment and training advice, environmental volunteering and the promotion of sustainability. Local craft enterprises are also set to benefit.
The Pontllanfraith building, erected in 1913, was the former Islwyn Council Building.
Katy Hollings, executive director of Groundwork, said: “This is a fantastic opportunity for us and it’s thanks to our partnership working that our bid has been successful. All parties involved have worked very hard in making this happen – and we have taken expert advice where needed.
“With this grant, we will be able to undertake major works on our outbuildings, which will provide workshops and facilities for our own work and for use by the community groups we work with.
“We are awaiting news on separate funding to refurbish the main building.
“2010 is our twentieth year of operation, and we are looking forward to celebrating our 21st in newly refurbished premises.”
Caerphilly Council leader Lindsay Whittle said: “We are delighted to be able to transfer this historic building over to our partners at Groundwork Caerphilly and it’s great to see that they will continue to use the site as a base to deliver a wide range of exciting schemes that are all helping to improve our local environment.”
Cllr Ron Davies, cabinet member for regeneration and countryside, said: “This significant grant from the Big Lottery Fund will enable the team to build on their successes to date and offer even more training and employment opportunities for local people. We will continue to work closely with Groundwork Caerphilly and look forward to the positive results that this close partnership will bring to our communities in the future.”