The monument at Conor Park will be dedicated at a service on Tuesday evening.
The 38-foot beam arrived in Yonkers on Aug. 28 board a flatbed truck draped in an American flag.
On Sunday, the city unveiled a plaque along the waterfront. It honors the 24 Yonkers residents who died on 9/11.
Elsewhere, police pipes and drums, a Boy Scout troop and 9/11 family members will be part of a twilight ceremony at The Rising memorial in Westchester County.
Officials say 111 Westchester residents and 12 former residents died on 9/11.
The ceremony will be held at the Kensico Dam in Valhalla.
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