Background　and　aims　Age-related　cognitive　impairment　impacts　a　significant　portion　of　the　elderly　population.　Remnant　cholesterol　(RC)　has　attracted　increased　attention　in　relation　to　cardiovascular　disease,　diabetes,　hypertension,　and　fatty　liver　disease.　Nevertheless,　its　role　in　cognitive　function　is　still　enigmatic,　prompting　our　exploration　into　the　potential　associations　between　them.Methods　A　total　of　1,331　participants　from　the　NHANES　(2011-2014)　database,　all　aged　over　60,　were　included　in　this　investigation.　Cognitive　function　was　assessed　using　four　widely　applied　tests,　including　the　Consortium　to　Establish　a　Registry　for　Alzheimer＇s　Disease　Word　Learning　(CERAD-WL),　CERAD　Delayed　Recall　(CERAD-DR),　Animal　Fluency　Test　(AFT),　as　well　as　Digit　Symbol　Substitution　test　(DSST).　Z-score　is　calculated　by　scores　from　the　above　four　tests.　The　association　between　RC,　total　cholesterol　(TC)　to　RC　and　cognitive　performance　was　assessed　by　logistic　regression　analyses.　In　addition,　restricted　cubic　spline　(RCS)　regression　was　performed　to　assess　non-linearity　between　RC　and　cognitive　function.　Subgroup　analysis　was　performed　to　evaluate　the　robustness　of　the　results　in　populations　with　relevant　covariate　variables.Results　Those　with　Z-scores　below　the　25%　quartile　are　defined　as　having　cognitive　impairment,　totaling　498　individuals.　Observationally,　higher　RC　levels　and　a　lower　TC/RC　were　associated　with　an　increased　risk　of　cognitive　impairment.　After　adjusting　for　confounding　factors,　the　impact　of　RC　levels　on　cognitive　performance　quartiles　was　consistent　across　various　subgroups,　except　in　individuals　with　trouble　sleeping,　no/unknown　alcohol　use,　and　no　hypertension.　Americans　with　high　RC　levels　and　trouble　sleeping　are　more　likely　to　develop　cognitive　impairment,　with　an　odds　ratio　of　2.33　(95%　CI:　1.18-4.59).Conclusion　This　study　suggests　that　higher　RC　levels　and　lower　levels　of　TC/RC　are　associated　with　an　increased　likelihood　of　cognitive　impairment,　suggesting　that　RC　can　serve　as　a　novel　and　convenient　indicator　for　predicting　the　risk　of　cognitive　impairment　in　the　US　population.