Cover Page - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Mar. 19, 2026	Jun. 30, 2025
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2025
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-42302
Entity Registrant Name	Chain Bridge Bancorp, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	20-4957796
Entity Address, Address Line One	1445-A
Entity Address, Address Line Two	Laughlin Avenue
Entity Address, City or Town	McLean
Entity Address, State or Province	VA
Entity Address, Postal Zip Code	22101
City Area Code	703
Local Phone Number	748-2005
Title of 12(b) Security	Class A common stock, par value $0.01 per share
Trading Symbol	CBNA
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
ICFR Auditor Attestation Flag	false
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 80,267
Documents Incorporated by Reference	Portions of Chain Bridge Bancorp, Inc.’s Proxy Statement to be filed with the United States Securities and Exchange Commission in connection with Chain Bridge Bancorp, Inc.’s 2026 Annual Meeting of Stockholders are incorporated by reference into Part III of this Form 10-K.
Entity Central Index Key	0001392272
Amendment Flag	false
Document Fiscal Year Focus	2025
Document Fiscal Period Focus	FY
Class A Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		3,322,762
Class B Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		3,239,055