More than 4,500 people signed up to take part in the full 13.1 mile course or a shorter three mile fun run, raising money for charity.
The annual event, organised by the Rotary Club of Brentwood a Becket, saw runners from all over the country and even from as far abroad as New York and Egypt take part.
Waiting at the start line in Sawyers Hall Lane, was one runner who counted this as his 204th half marathon.
The full course wound its way through Shenfield towards Blackmore before making its way back to the bottom of Sawyers Hall Lane.
One runner, Chris Kay, 25, from Cumbria, said that he was using the half marathon as a way of training himself to run full marathon distances: "I completed the Blackpool Half Marathon in January, so this is another step up," he said.
Charities had a large presence at the runs.
Siblings Ellen and Adam Garrod were running the half marathon for Brentwood charity Special Needs And Parents, where they volunteer.
Speaking of the cold and snowy conditions, Ellen, 20, said:"They made the right decision – it took a lot of guts to go ahead."
Stuart Austin, 35, was running with 10-year-old CallumRossiter dressed as Where's Wally to raise money for Havering's Saint Francis Hospice.
"The costume was Callum's idea," Mr Austin said.
Mary Heartshorne, 19, was helping raising money for the Explorer Scouts to go to Kenya to work in Nairobi's slums. 15 Scouts took part in the fun run – including one dressed as an inflatable horse.
More than 100 runners, including 30 between eight and 11 years old, ran in memory of 14-year-old Georgia Cordery, who lost her battle against cancer in 2010.
Non-running members were also getting into the community spirit: staff and students from the local Becket Keys Church of England school were on hand to provide entertainment with a choir and orchestra, while students guided runners and spectators with giant foam hands.
Emma-Jane Sharp, a teacher at the school, said: "There are 70 of us here, both students and parents, doing our bit to help the community."
Ann Cardus sold 200 cakes from the driveway of her house on Highland Avenue with three other friends to raise money for Hopefield Animal Sanctuary, keeping frozen spectators warm with food and drink.
"This is my way of making a difference," she said.
The half marathon was won by Ryan Prout in a time of 1h 9m and 47s. Paul Molyneux, who led for most of the race, came in second, a mere seven seconds behind him and Crispian Bloomfield came third.
