| Official Name: | Portencross |
| Gaelic Name: | Port na Crois |
| Country: | Scotland |
| Unitary Scotland: | North Ayrshire |
| Lieutenancy Scotland: | Ayrshire and Arran |
| Coordinates: | 55.7°N -58°W |
| Static Image: | Portencross from the pier.jpg |
| Static Image Caption: | Portencross viewed from its pier |
| Os Grid Reference: | NS176489 |
| Post Town: | WEST KILBRIDE |
| Postcode Area: | KA |
| Postcode District: | KA23 |
| Dial Code: | 01294 |
| Constituency Westminster: | North Ayrshire and Arran |
| Constituency Scottish Parliament: | Cunninghame North |
Portencross (Gaelic; Scottish Gaelic: Port na Crois) is a hamlet near Farland Head in North Ayrshire, Scotland. Situated about 3km (02miles) west of Seamill and about 2km (01miles) south of Hunterston B nuclear power station, it is noted for Portencross Castle.
It has two harbours and a pier. The "Old Harbour" is actually a small tidal inlet next to the castle, and is part of the castle property. The larger harbour, "North Harbour", owned by the Portencross Harbour Trust, lies about 100m (300feet) north of the castle and was the main access point for fishing activity.[1]
The Portencross Pier was built in the era of Clyde steamer cruising but was never used as much as other locations such as Largs, Fairlie or Wemyss Bay.
In 2014 the North Ayrshire Ranger Service carried out a survey of the plants growing on the rocky shore, whinstone dyke, saltmarsh and "machair-like" seaside vegetation. Species recorded included sea arrowgrass (Triglochin maritima); sea sandwort (Honkenya peploides); scurvy-grass (Cochlearia officinalis); common orache (Atriplex patula); sea club-rush (Scirpus maritimus); sea milkwort (Glaux maritima); salt mud-rush (Juncus gerardii); lesser sea spurrey (Spergularia marina); cliff sand spurrey (Spergularia rupicola); sea aster (Aster tripolium); red bartsia (Odonitites verna); silverweed (Potentilla anserina); bird's foot trefoil (Lotus geniculatus); sea pink/thrift (Armeria maritima); eyebright (Euphrasia nemorosa); yellow rattle (Rhinanthus minor); sea plantain (Plantago maritima); meadow cranesbill (Geranium pratense); purple loosetrife (Lythrum salicalia); pineapple weed (Matricaria matricariodes); curled dock (Rumex crispus); scentless mayweed (Matricaria maritima); corn sowthistle (Sonchus arvensis); marsh thistle (Cirsium palustre); lady's bedstraw (Galium verum); mugwort (Artemisia vulgaris); celery-leaved crowfoot (Ranunculus scleratus); ragged robin (Lychnis flos-cuculi); yellow flag iris (Iris pseudacorus); parsley water-dropwort (Oenanthe lachenalii); greater woodrush (Luzula sylvatica); amphibious bistort (Polygonum amphibian); crow garlic (Allium vineale var. compactum); Japanese rose (Rosa rugosa); alder (Alnus glutinosa); sea buckthorn (Hippophae rhamnoides); wood sage (Teucreum scorodonia); hemlock water-dropwort (Oenanthe crocata); sticky groundsel (Senecio viscosus); bloody cranesbill (Geranium sanguineum); bracken/brake (Pteridium aquilinium); yellow splash lichen (Xanthoria parietina); crab's eye lichen (Ochrolechia parella); sea ivory (Ramalina siliquosa).