| Country: | TWN |
| Type: | PH |
| Route: | 6 |
| Alternate Name: | Old Houwen Highway |
| Map Custom: | yes |
| Length Km: | 31.388 |
| Direction A: | North |
| Terminus A: | in Houlong |
| Junction: | in Houlong in Gongguan |
| Direction B: | South |
| Terminus B: | in Wenshui, Shitan |
| Previous Type: | PH |
| Previous Route: | 5 |
| Next Type: | PH |
| Next Route: | 7 |
Provincial Highway 6 is a highway connecting Houlong, Miaoli and Dahu, Miaoli. The entire highway is within Miaoli County. The highway is now primarily used for local access after the completion of (Provincial Highway 72), an expressway running parallel to the highway.
The route is a major highway in Miaoli County, as it connects the coastal townships in Miaoli with the mountainous ones. It is also known as Old Houwen Highway (舊後汶公路) since the terminus of the highway is Houlong and Wenshui (汶水), a village in Shitan.
The highway begins at Xibin Expressway (西濱快速道路), also known as PH 61, in the coastal township of Houlong. The highway closely follows Houlong River, passing through junctions with PH 1, Freeway 3, PH 13 as it reaches Miaoli City. The highway continues to head south towards Gongguan, where it meets Freeway 1. Highway 4 reaches its terminus at an intersection with PH 3 at the border of Shitan and Dahu townships.
http://www.thb.gov.tw/ (National Highway Bureau, in Traditional Chinese)