Bath Lane is effectively a spur of East Street, down to the quay and amenities which lay at the bottom. William Deane, who lived in Fairfield House on East Street, gave some of his land as a gift to the people of Fareham, as what is now known as Bath Lane recreation ground. For years this was Fareham's only park, and it was used by the community for various events and exercises, and it also meant that this road was originally called Park Lane.
In 1838, a bathing house was built at the end of the road, using water from the creek, to allow men and women to bathe separately. As a result, the road became known as Bathing House Lane, which was later adopted as its formal name, although maps don't seem to have reflected this.
At the start of the 20th Century, the bathing house closed (to become cottages), so the name was shortened to Bath Lane. Swimming in the creek continued to be a popular pastime until the mid-1950s, where the silting up and pollution (it was never clean by today's standards, but discarded German submarines apparently made it worse) put an end to it for most people.
Houses were built in the 1930s and 1940s, and at the far end, former gas works were converted in to houses at the start of the 21st Century. The quay here was known variably as Bathing House Quay and Gas Works Quay.
Deanes Park Road, named in honour of William Deane and his gift, was started at the start of the century as a cul-de-sac, meeting Bath Lane at one end and a track known as the Esplanade at the other (grammatical enthusiasts will be keen to know it was once apostrophised, but that appears to have been dropped with time). When Eastern Way opened in 1971, Bath Lane was severed, and alternative access was required. Since land was being reclaimed anyway at the Delme Roundabout, Deanes Park Road was extended on to the creek and through the railway arches to meet the new road.
Meanwhile, Bath Lane was now divided in to two, with about seven houses lost to the new road, one of which formed access for a new car park. This created Lower and Upper Bath Lane - the embankment of the railway line masks the height difference between the two.