Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2023	Mar. 28, 2024	Jun. 30, 2023
Document And Entity Information
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Entity File Number	000-21344
Document Period End Date	Dec. 31, 2023
Entity Registrant Name	FIRST KEYSTONE CORPORATION
Entity Incorporation, State or Country Code	PA
Entity Tax Identification Number	23-2249083
Entity Address, Address Line One	111 West Front Street
Entity Address, City or Town	Berwick
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	18603
City Area Code	570
Local Phone Number	752-3671
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer
Entity Public Float			$ 102,550,198
Title of 12(g) Security	Common Stock, par value $2.00 per share
Entity Common Stock, Shares Outstanding		6,019,152
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Auditor Name	Baker Tilly US, LLP
Auditor Firm ID	23
Auditor Location	Iselin, New Jersey
Entity Small Business	true
Entity Central Index Key	0000737875
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Amendment Flag	false