Document and Entity Information - shares	9 Months Ended
	Oct. 31, 2018	Dec. 07, 2018
Document and Entity Information
Entity Registrant Name	MESABI TRUST
Entity Central Index Key	0000065172
Document Type	10-Q
Document Period End Date	Oct. 31, 2018
Amendment Flag	false
Current Fiscal Year End Date	--01-31
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding		13,120,010
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3