@Rallynow,
As Bill suggests, this has come up before but I can't find the right word combo to recover it (and it's getting late!).
If this is from the Osprey Campaign "Trenton & Princeton 1776-77" then I have a feeling that the author is causing confusion by giving two completely different units the same name. Hand's regiment is the 1st Continental Regt of 1776, also known as the Pennsylvania Rifle Regt, which Brechtel has referred to above (except to say that it had 8, and later 9 companies, not just the original 6); the unit commanded by Williams is, I think, the remains of the Pennsylvania State Rifle Regiment, originally led by Colonel Samuel Miles, and possibly also the remnants of the Pennsylvania State Musketry Battalion which was led by Colonel Samuel Atlee .
Both the latter units were State militia raised in March 1776; they formed part of Stirling's Brigade of Sullivan's Division at Long Island, but were at opposite ends of Sullivan's line – the rifles were on his far left whilst Atlee's men initially defended the Vechte-Cortelyou House at Gowanus, which Smallwood's unit famously tried to recapture. Both PA units suffered heavy losses, 210 and 90 respectively, and both Atlee and Miles were captured (Hand's Regt was part of Nixon's Brigade of Greene's Division, so is clearly distinct).
These two units later became the 13th Pennsylvania Regt in November 1777, and were subsequently merged into the 2nd Pennsylvania Regt in June 1778. The combined unit fought as part of Weedon's Virginia brigade at Brandywine, and also at Germantown, being commanded in both by Walter Stewart. It seems to have worn blue coats faced red (and possibly also blue faced white), based on reports of four deserters from August 1777 (and one from March 1777), in these two actions. Prior to that, Miles corps wore light coloured hunting shirts and possibly caps instead of hats; whilst Atlee's eventually received blue coats faced red, with yellow lacing for their hats (and was one of the units mistaken for Hessians during the battle of Long Island).
I don't know if this is of interest, but you can access a journal (via Fold3) kept by Ennion Williams for 1775, when he journeyed to Cambridge to serve under Washington – I'm afraid I can't access it, so I don't know when it goes up to:-
fold3.com/document/3089581
There is also a portrait of Ennion Williams c.1777 by Charles Wilson Peale:-
link