The Continental Army relied on the various colonial committees to obtain most of its supplies. Washington wrote dozens of appeals to those committees in hopes of finding enough gunpowder and other war material to sustain his army.
"our publick Capacity, & the Hope that you will be both able & willing, to give us some Assistance, has led me to make this Application. The Situation of the Army, as to Ammunition, is by no Means what it ought to be. We have great Reason to suspect, the Enemy very soon intend to bombard our Lines; & our Stock of Powder is so small, as in a great Degree to make our heavy Artillery useless. I must therefore request you will exert yourselves to forward, whatever can be spared from your Province, as soon as possible. The Necessity is great, the Cause is of the last Importance; I am therefore perswaded, I need use no Arguments to quicken your Zeal. The smallest Quantities are not beneath Notice, as a considerable Stock may be formed from various Collections. Lead & Flints, are also very scarce, you will therefore furnish all you can spare."
George Washington, letter to the New Hampshire Committee of Safety, 4 August 1775founders.archives.gov
https://history.army.mil/Publications/Publications-Catalog/The-Canadian-Campaign/