Cover - shares	6 Months Ended
	Jun. 30, 2024	Aug. 09, 2024
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2024
Document Transition Report	false
Entity File Number	000-56075
Entity Registrant Name	4Front Ventures Corp.
Entity Incorporation, State or Country Code	A1
Entity Tax Identification Number	83-4168417
Entity Address, Address Line One	7010 E. Chauncey Lane
Entity Address, Address Line Two	Suite 235
Entity Address, City or Town	Phoenix
Entity Address, State or Province	AZ
Entity Address, Postal Zip Code	85054
City Area Code	602
Local Phone Number	428-5337
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		913,923,993
Entity Central Index Key	0001783875
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q2
Amendment Flag	false
Class A Subordinate Voting Share | OTCQX MARKETPLACE
Document Information [Line Items]
Title of 12(b) Security	Class A Subordinate Voting Shares, no par value
Trading Symbol	FFNTF
Class A Subordinate Voting Share | CANADIAN SECURITIES EXCHANGE
Document Information [Line Items]
Title of 12(b) Security	Class A Subordinate Voting Shares, no par value
Trading Symbol	FFNT