Exhibit 99.1

PRESS RELEASE

FOR IMMEDIATE RELEASE

ACNB CORPORATION Announces Updated

Loan Modification and Deferral Information

GETTYSBURG, PA, September 24, 2020 --- ACNB Corporation (NASDAQ: ACNB) announced that its wholly-owned banking subsidiary, ACNB Bank, has experienced a substantial decrease in the number and amount of loans subject to temporary modification or deferral due to the economic impacts of the Coronavirus Disease 2019 (COVID-19) pandemic. As of June 30, 2020, ACNB Bank reported approved loan modifications and deferrals for 466 loans totaling $234.6 million in principal balances, representing 13.5% of the total loan portfolio. As of August 31, 2020, ACNB Bank has outstanding approvals for loan modifications and deferrals for 88 loans totaling $86.7 million in principal balances, representing 5.0% of the total loan portfolio.

James P. Helt, President & Chief Executive Officer of ACNB Corporation and ACNB Bank, noted, “Government public health measures relating to the COVID-19 pandemic and significant curtailment of consumer spending has had a significant effect on the economies of the communities served by ACNB Corporation. Upon announcement of the government measures earlier this year, ACNB Bank anticipated receiving a significant number of requests for loan modifications and deferrals from its commercial and consumer customers and developed a vigorous program to work with customers through this difficult time. Overall, we are pleased that the demand for loan modification and deferral requests has resulted in a decrease in our preliminary estimates of potential defaults and loan losses. Reduced demand for loan modifications and deferrals reflects the strength and resilience of our customer base and the quality of our underwriting standards. ACNB Bank continues to work with customers on a case-by-case basis and to monitor the loan portfolio, economic factors, governmental responses to the pandemic, and their interrelated effects.”

ACNB Corporation

Press Release/Updated Loan Modification and Deferral Information

September 24, 2020

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ACNB Corporation, headquartered in Gettysburg, PA, is the $2.4 billion financial holding company for the wholly-owned subsidiaries of ACNB Bank, Gettysburg, PA, and Russell Insurance Group, Inc., Westminster, MD. Originally founded in 1857, ACNB Bank serves its marketplace with banking and wealth management services, including trust and retail brokerage, via a network of 21 community banking offices, located in the four southcentral Pennsylvania counties of Adams, Cumberland, Franklin and York, as well as loan offices in Lancaster and York, PA, and Hunt Valley, MD. As divisions of ACNB Bank operating in Maryland, FCB Bank and NWSB Bank serve the local marketplace with a network of five and seven community banking offices located in Frederick County and Carroll County, MD, respectively. Russell Insurance Group, Inc., the Corporation’s insurance subsidiary, is a full-service agency with licenses in 44 states. The agency offers a broad range of property, casualty, health, life and disability insurance serving personal and commercial clients through office locations in Westminster, Germantown and Jarrettsville, MD, and Gettysburg, PA. For more information regarding ACNB Corporation and its subsidiaries, please visit acnb.com.

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ACNB Corporation

Press Release/Updated Loan Modification and Deferral Information

September 24, 2020

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FORWARD-LOOKING STATEMENTS - In addition to historical information, this press release may contain forward-looking statements. Examples of forward-looking statements include, but are not limited to, (a) projections or statements regarding future earnings, expenses, net interest income, other income, earnings or loss per share, asset mix and quality, growth prospects, capital structure, and other financial terms, (b) statements of plans and objectives of management or the Board of Directors, and (c) statements of assumptions, such as economic conditions in the Corporation’s market areas. Such forward-looking statements can be identified by the use of forward-looking terminology such as “believes”, “expects”, “may”, “intends”, “will”, “should”, “anticipates”, or the negative of any of the foregoing or other variations thereon or comparable terminology, or by discussion of strategy. Forward-looking statements are subject to certain risks and uncertainties such as local economic conditions, competitive factors, and regulatory limitations. Actual results may differ materially from those projected in the forward-looking statements. Such risks, uncertainties and other factors that could cause actual results and experience to differ from those projected include, but are not limited to, the following: the effects of governmental and fiscal policies, as well as legislative and regulatory changes; the effects of new laws and regulations, specifically the impact of the Tax Cuts and Jobs Act and the Dodd-Frank Wall Street Reform and Consumer Protection Act; impacts of the capital and liquidity requirements of the Basel III standards; the effects of changes in accounting policies and practices, as may be adopted by the regulatory agencies, as well as the Financial Accounting Standards Board and other accounting standard setters; ineffectiveness of the business strategy due to changes in current or future market conditions; future actions or inactions of the United States government, including the effects of short- and long-term federal budget and tax negotiations and a failure to increase the government debt limit or a prolonged shutdown of the federal government; the effects of economic conditions particularly with regard to the negative impact of severe, wide-ranging and continuing disruptions caused by the spread of Coronavirus Disease 2019 (COVID-19) and the responses thereto on the operations of the Corporation and current customers, specifically the effect of the economy on loan customers’ ability to repay loans; the effects of competition, and of changes in laws and regulations on competition, including industry consolidation and development of competing financial products and services; the risks of changes in interest rates on the level and composition of deposits, loan demand, and the values of loan collateral, securities, and interest rate protection agreements, as well as interest rate risks; difficulties in acquisitions and integrating and operating acquired business operations, including information technology difficulties; challenges in establishing and maintaining operations in new markets; the effects of technology changes; volatilities in the securities markets; the effect of general economic conditions and more specifically in the Corporation’s market areas; the failure of assumptions underlying the establishment of reserves for loan losses and estimations of values of collateral and various financial assets and liabilities; acts of war or terrorism; disruption of credit and equity markets; the ability to manage current levels of impaired assets; the loss of certain key officers; the ability to maintain the value and image of the Corporation’s brand and protect the Corporation’s intellectual property rights; continued relationships with major customers; and, potential impacts to the Corporation from continually evolving cybersecurity and other technological risks and attacks, including additional costs, reputational damage, regulatory penalties, and financial losses. We caution readers not to place undue reliance on these forward-looking statements. They only reflect management’s analysis as of this date. The Corporation does not revise or update these forward-looking statements to reflect events or changed circumstances. Please carefully review the risk factors described in other documents the Corporation files from time to time with the SEC, including the Annual Reports on Form 10-K and Quarterly Reports on Form 10-Q. Please also carefully review any Current Reports on Form 8-K filed by the Corporation with the SEC.

ACNB #2020-26

September 24, 2020