Bomb disposal experts were called to a park in Devon after the discovery of a ordnance device.
Devon and Cornwall Police said the bomb, believed to be a World War II munition, was found at Devonport Park in the Stoke area of Plymouth.
A 200m (656ft) cordon was initially put in place when the bomb was discovered at about 1140 GMT, but that has now been removed.
A police spokesman said the bomb was not thought to be "viable".
Last month part of Plymouth city centre was evacuated when a partially buried German World War II bomb was found by workmen at a building site in Notte Street.