Boston Manor House
Located just south of Boston Manor underground station (Piccadilly Line), this Jacobean house is where folklore suggests King Charles I watched the Battle of Brentford, though this appears unlikely.  

Turnham Green
The remaining open spaces of Back Common, Acton Green and Turnham Green are all that remains of the common over which the royalist and parliamentarian armies faced each other the day after the Battle of Brentford. Turnham Green is the second largest confrontation of the civil war in terms of numbers deployed on the battlefield; only Marston Moor in 1644 surpasses it.  A small sign opposite Turnham Green underground station on the edge of Acton Green Common commemorates the battle.  

Hyde Park 
The earthworks in Hyde Park running parallel with Park Lane are is the only established remnants, save the names of some London streets and, possibly, other earthworks in Southwark park, of the civil war defences of London - the Lines of Communication.  These were eleven miles of earthen walls and fortifications which were built rapidly in late 1642 and the first half of 1643 to defend against a royalist attack on London, Westminster and Southwark.