A public reading of the Declaration of Independence July 4, 1776

Was the Declaration of Independence read on July 4 1776?

The answer would seem to be yes.
In this article Chris Coelho lays out the case which can be summarized as:
1. There's pretty good evidence the hand written copy brought to the printer on July 4th had diacratic marks on it to aid in a public reading.
2. Several people at the time made note of a public reading in their diaries or letters.
3. A few others who were in the vicinity (including one who practically lived next door to the State house) in later life wrote that they heard it.

Who heard it? Mostly the people who happened to be in or near there (the State House yard) and perhaps some of the Timothy Matlack's associates whom he might have sent word to.

Who was Timothy Matlack? At the time he was a clerk and top penman for Charles Thomson, the Continental Congress's Secretary. Both were considered 'radical.' Radical was used to describe all those who had been advocating for independence as opposed to the men of 'moderation' who wanted to move in that direction only if it became neccessary. In Matlack's case, 'radical' also meant an advocate for a much more democratic distribution of power in Pennsylvania.
The First Public Reading of the Declaration of Independence, July 4, 1776 - Journal of the American Revolution

In the article 'Associators' refers to Pennsylvania's form of militia - voluntary because the colony's pacifist history. However, they were mostly equiped and paid etc by the assembly, and eventually served under terms of the articles of war which they negotiated.