The empty landmark building has been transformed into a "unique office space for digital start-up businesses" with 25 offices meeting rooms, and conference facilities.
Companies are already expressing interest in working in the unique surroundings with opportunities for networking and sharing the latest innovations and technology.
The renovation was funded by Swindon and Wiltshire Local Enterprise Partnership, which successfully bid for £169m from the Government's Local Growth Fund.
Digital Mansion was officially opened on Friday (March 22) by Paddy Bradley, director of SWLEP and Baroness Scott, leader of Wiltshire Council.
“We are creating something really special here right in the heart of Wiltshire," said Baroness Scott.
“We want to attract the brightest and best minds to use this unique space and be supported in taking their ideas forward. At Wiltshire Council we don’t just talk about the economy we actively engage in creating the right space where great ideas can flourish.”
SWLEP chairman John Mortimer said: "Supporting the growth and strengthening the competitiveness of small and medium sized businesses is one of the investment priorities for the Swindon and Wiltshire Local Enterprise Partnership.
"I am delighted to see the completion of this project, the Corsham Digital Mansion will be a hub of collaboration and business growth in Corsham and will build on the town's growing reputation for digital communication and technologies.”
Also in attendance was Jake Berry MP, minister for Local Growth, who said: "This Government is committed to boosting economic growth across the whole of the UK and building a Britain fit for the future.
“An investment of £2.5 million from the Local Growth Fund has enabled the redevelopment of Corsham Mansion House, bringing this historic site back into use for the 21st century as a centre for digital innovation which will create new jobs and opportunities to attract investment into the area.”