The Isehara Love Hotel District is in southern Kanagawa Prefecture. It's on a wooded hillside, with only a single road going through, so it's somewhat isolated from the surrounding area. I counted twelve love hotels, ranging from a tiny five room motel to large, luxurious looking establishments. It must have been a happening place in its heyday, but when I visited in December 2015 it had clearly seen better days, and at least half the hotels had gone out of business.
The hotels that remained open didn't show any obvious signs of decline, and looked inviting as night fell. However, given Japan's unfavourable demographics, I expect their ranks to be further thinned in the coming years.