Why is the detour so long?

Unfortunately, there are quite a few access constraints in this area. Old Northern Road is the main access road to Wisemans Ferry. There are other local road detours in the vicinity such as River Road, however we do not recommend road users to take this alternate route due to the condition of the road. The safest and recommended alternate route for all vehicles is via the M1, using the Peats Ridge Road exit, then along Wisemans Ferry Road to access the northern side of the Hawkesbury. If you need to cross into Wisemans Ferry township, this can be done using the Ferry crossing which takes approximately 4 minutes.