If you search for "Nagao Jinya Site" on Google Maps, a photo of a temple gate shows up, but that is actually "the gate of Entsū-ji in Tsuda Motomachi, said to have been relocated" from the Kugai clan's Nagao Jinya site, and even though it's in the same Hirakata City, it's a different location. Also, the point shown on the map is just one spot within the former Nagao Jinya site, and there's no explanation board on site describing the jinya's extent or its history from establishment to abolition.

There's nothing here either. An explanation board, a stone monument, anything would do, but without something, especially in front of a school, you just look suspicious. After all, hardly anyone goes around touring castles that aren't famous ones.

No remains, no explanation board.