Drivers can expect longer journeys when a road shuts for more than two months.
The road at White Ash Green is due to be closed from its junction with Bradleys Lane for 68 days.
The road runs between Halstead and Gosfield.
The closure is needed while work is carried out by Cadent, starting on May 30.
Cadent will shut the road while its conducts gas mains replacement work.
The Essex Highway's official diversion will take drivers via the A131, Halstead Road and the A1017.
Overall, it would divert drivers by six miles.
A spokesman for Essex Highways said: "The closure is scheduled to commence on May 30 for 68 days.
"The closure is required for the safety of the public and workforce while mains replacement works are undertaken by Cadent.
"An alternative route is available via Mount Hill, Braintree Road, Bournebridge Hill, Pennypot Corner, Halstead Road, Gosfield Road, The Street, Halstead Road, White Ash Green and vice versa.
"Access for emergency service vehicles and pedestrians will be maintained at all times during the closure."
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