| Cover | Dec. 10, 2024 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Dec. 10, 2024 |
| Entity File Number | 000-19028 |
| Entity Registrant Name | Muncy Columbia Financial Corporation |
| Entity Central Index Key | 0000731122 |
| Entity Tax Identification Number | 23-2254643 |
| Entity Incorporation, State or Country Code | PA |
| Entity Address, Address Line One | 232 East Street |
| Entity Address, City or Town | Bloomsburg |
| Entity Address, State or Province | PA |
| Entity Address, Postal Zip Code | 17815 |
| City Area Code | 570 |
| Local Phone Number | 784-4400 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
