The demonstrators, many wearing balaclavas, gathered on the street early in the day after the court's decision came down overnight. Garvaghy Road runs through a part of Portadown where many residents favor unification with the Republic of Ireland.
The standoff pushed tensions in the area to a boiling point. Portadown has a long history as a flashpoint for sectarian conflict, and this parade route in particular has triggered unrest before. The protesters made clear they had no intention of letting the Orange Order through, regardless of what the High Court decided hours earlier.
The clash shows how a decades-old dispute over a single stretch of road can still bring a town to a standstill. Nearly three decades after the last time this parade went down Garvaghy Road, a court order was enough to authorize it but not enough to make it happen.