Exhibit 99.1

Press Release – For Immediate Release

Friday, July 18, 2025

Mifflinburg Bancorp, Inc., Reports Second Quarter 2025 Earnings

Mifflinburg, PA – Mifflinburg Bancorp, Inc. (“Company”) (OTCID: MIFF), parent company of Mifflinburg Bank and Trust Company (“Bank”), has released its unaudited consolidated financial statements for the second quarter of 2025.

Financial Results

Net income, as reported under U.S. Generally Accepted Accounting Principles (“GAAP”), for the quarter-ended June 30, 2025 was $1,820,000 compared to $1,323,000 for the same period in 2024, a 37.6% increase. Net income year-to-date for 2025 was $3,626,000 compared to $2,679,000 for the same period in 2024, a 35.3% increase. Basic and diluted earnings per share for the quarters-ended June 30, 2025 and 2024 were $0.98 and $0.71, respectively. Return on average assets and return on average equity were 1.20% and 12.37% for the quarter ended June 30, 2025 compared to 0.93% and 9.68% for the same period of 2024.

Net interest income for the three months ended June 30, 2025 was $5.0 million compared to $4.0 million for the same period in 2024, a 24.0% increase. Net interest income for the six months ended June 30, 2025 was $9.7 million compared to $7.9 million for the same period in 2024, a 23.9% increase. The significant increase in net interest income is primarily driven by loan growth of 7.2% year-to-date for 2025, compared to loan growth of 4.2% year-to-date for the same period in 2024 and by market interest rates starting to decline thus slowing the increase in cost of funds. Yield on earning assets increased 54 basis points, to 5.22% for the quarter-ended June 30, 2025 compared to the quarter-ended June 30, 2024, while the cost of funds increased 13 basis points, to 2.36%, as compared to the same time period in 2024. The net interest margin increased from 2.96% for the quarter-ended June 30, 2024 to 3.41% for the quarter-ended June 30, 2025.

The Bank recorded a provision for credit losses of $192,000 for the three months ended June 30, 2025, offset by a $36,000 reduction in the unfunded commitment reserve. The Bank recorded a provision for credit losses of $262,000 for the six months ended June 30, 2025, offset by a $100,000 reduction in the unfunded commitment reserve. The Bank recorded a provision for credit losses of $30,000 for the three and six months ended June 30, 2024.

Non-interest income for the three months ended June 30, 2025 was $527,000 compared to $415,000 for the same period in 2024, a 27.0% increase. The increase in non-interest income is primarily the result of a $73,000 decrease in net marketable equity security losses. Non-interest income for the six months ended June 30, 2025 was $1.1 million compared to $1 million for the same period in 2024, a 12.6% increase. The increase in non-interest income year-to-date is primarily the result of a $52,000 gain on sale of premises and a $44,000 increase on service charges.

Non-interest expense for the three months ended June 30, 2025 was $3.1 million compared to $2.8 million for the same period in 2024, a 10.1% increase. The increase in non-interest expense is primarily the result of an increase of $118,000 in salaries and employee benefits and merger expenses totaling $85,000 that were recorded in the second quarter of 2025. Non-interest expense for the six months ended June 30, 2025 was $6.2 million compared to $5.7 million for the same period in 2024, a 10.0% increase. The increase in non-interest expense year-to-date is primarily the result of merger expenses totaling $248,000 that were recorded in the first half of 2025 and an increase of $162,000 in salaries and employee benefits.

An income tax provision of $407,000 was recorded for the three months ended June 30, 2025, compared to an income tax provision of $238,000 for the three months ended June 30, 2024, a 71.0% increase. An income tax provision of $827,000 was recorded for the six months ended June 30, 2025, compared to an income tax provision of $469,000 for the same period in 2024, a 76.3% increase. The increase in the tax provision is primarily the result of non-deductible merger expenses and by tax-exempt interest income representing a smaller percentage of total interest income and increased pre-tax income compared to the same time periods in the prior year.

Financial Condition

Total assets increased to $629.2 million as of June 30, 2025 from $596.7 million as of December 31, 2024, an increase of 5.5%. Cash and cash equivalents increased $11.8 million from December 31, 2024 to June 30, 2025. Net loans increased by $31.0 million, or 7.2%, offset by securities available for sale decreasing $8.9 million and by interest-bearing time deposits decreasing $1.7 million from December 31, 2024 to June 30, 2025. Total deposits increased $25.1 million from December 31, 2024 to June 30, 2025, and Federal Home Loan Bank advances increased $4.0 million from December 31, 2024 to June 30, 2025.

When compared to December 31, 2024, stockholders’ equity, excluding accumulated other comprehensive loss, increased $2.3 million to $62.6 million as of June 30, 2025. For the quarter-ended June 30, 2025 cash dividends of $0.74 per share were paid to stockholders, as compared to $0.72 for the same period in 2024. Mifflinburg Bancorp, Inc. remains well capitalized, with an equity-to-assets ratio of 9.4% as of June 30, 2025 and December 31, 2024.

The Bank maintained a strong liquidity position as of June 30, 2025, with additional borrowing capacity with the Federal Home Loan Bank of Pittsburgh of $155.3 million and $1.3 million in additional borrowing capacity from the Federal Reserve’s Discount Window.

About Mifflinburg Bancorp, Inc.

Mifflinburg Bancorp, Inc. is a bank holding company organized under the Pennsylvania Business Corporation Law on February 3, 1986. The assets are primarily those of its wholly owned subsidiary, Mifflinburg Bank and Trust Company, established in 1872. Mifflinburg Bank and Trust Company is a full-service commercial bank servicing customers from seven locations in Union, Snyder, Northumberland and Centre counties.  The Company has 80 employees as of June 30, 2025, and total assets of $629 million.

Cautionary Note Regarding Forward Looking Statements

This press release contains forward-looking statements as defined in the Private Securities Litigation Reform Act of 1995.  Such forward-looking statements about Mifflinburg Bancorp, Inc. (“MIFF”) and Northumberland Bancorp (“NUBC”), together with their respective banking subsidiaries, Mifflinburg Bank and Trust Company and The Northumberland National Bank, may include beliefs, goals, intentions and expectations and involve substantial risks and uncertainties.  Statements other than statements of current or historical fact, including statements regarding future financial condition, results of operations, business plans, liquidity, cash flows, projected costs, and the impact of any laws or regulations applicable to MIFF or NUBC are forward-looking statements.  Words such as “anticipates,” “believes,” “estimates,” “expects,” “forecasts,” “intends,” “plans,” “projects,” “may,” “will,” “should,” and other similar expressions are intended to identify these forward-looking statements.  Such statements are subject to factors that could cause actual results to differ materially from anticipated results.  Among the risks and uncertainties that could cause actual results to differ from those described in the forward-looking statements include, but are not limited to the following: (1) costs or difficulties related to integration of the two companies following the merger; (2) the risk that the anticipated benefits, cost savings and any other savings from the merger may not be fully realized or may take longer than expected to realize; (3) changes to interest rates; (4) the ability to control costs and expenses; (5) general economic conditions; (6) adverse developments in borrower industries and, in particular, declines in real estate values; (7) MIFF’s ability to maintain compliance with federal and state laws that regulate its business and capital levels; (8) MIFF’s ability to reais capital as needed by its business; and (9) the other factors discussed in other reports MIFF may file with the Securities and Exchange Commission (“SEC”).  Neither MIFF nor NUBC undertake and each specifically disclaims any obligation to publicly release any revisions which may be made to any forward-looking statements to reflect the occurrence of anticipated or unanticipated events or circumstances after the date of such statements.  You are cautioned not to place undue reliance on these forward-looking statements.