Sha'ar Poleg Nature Reserve, Nature reserve in Central District, Israel

Sha'ar Poleg Nature Reserve covers 136.5 dunams around the second of the three kurkar ridges along the southern Sharon coast, with Tel Poleg rising 20–25 m above sea level. The Poleg Stream runs through a breach in the ridge, 10 m wide at its base and 20 m at the top. West of the ridge lie an abandoned kurkar quarry and a winter pool; east of the tell, a marsh of common reed.

A Canaanite settlement stood on the kurkar ridge at Tel Poleg from the early 3rd millennium BCE, 20–25 m above the sea. From the 19th century BCE a moat was cut on its north side and widened in the Roman period, when marsh drainage began; the Poleg Stream runs through this breach, 10 m wide at its base and 20 m at the top. The Mamluks let the drainage works lapse and a 4,000-dunam marsh formed east of the ridge; after Jewish institutions bought the land in 1935 the breach was deepened and the marsh drained.

The name Poleg comes from the Hebrew word miflag, meaning a breach, after the 10-metre-wide gap in the kurkar ridge through which the stream flows. The Crusaders called the stream Nahal HaSela HaMevuteret, the stream of the split rock, and Arabic speakers knew it as Wadi Falik, the crossing. In the pine grove planted at the first settlement of Udim in 1948, residents raised a monument to three members of the moshav killed defending it.

The reserve lies between Yakum to the south, Odim to the north, Route 2 to the east and the Wingate Institute to the west. A pine grove with a picnic corner stands by the memorial to three residents of the first Odim settlement. The winter pool fills in the rainy season, and a small marsh persists into summer.

The reserve holds both Iris atropurpurea and Iris vartanii, two coastal irises that flower in different seasons, alongside geophytes such as Sternbergia and cyclamen. The Iris Reserve name is not used in the sources; the plants grow within the 136.5-dunam reserve itself.