Context : Radio continuum surveys of the Galactic plane can find and characterize H ii regions , supernova remnants ( SNRs ) , planetary nebulae ( PNe ) , and extragalactic sources .
A number of surveys at high angular resolution ( \leq 25 ^ { \prime \prime } ) at different wavelengths exist to study the interstellar medium ( ISM ) , but no comparable high-resolution and high-sensitivity survey exists at long radio wavelengths around 21 cm .

Aims : Our goal is to investigate the 21 cm radio continuum emission in the northern Galactic plane at < 25″ resolution .

Methods : We observed a large fraction of the Galactic plane in the first quadrant of the Milky Way ( l = 14.0 - 67.4 \degr and |b| \leq 1.25 \degr ) with the Karl G. Jansky Very Large Array ( VLA ) in the C-configuration covering six continuum spectral windows .
These data provide a detailed view on the compact as well as extended radio emission of our Galaxy and thousands of extragalactic background sources .

Results : We used the BLOBCAT software and extracted 10916 sources .
After removing spurious source detections caused by the sidelobes of the synthesised beam , we classified 10387 sources as reliable detections .
We smoothed the images to a common resolution of 25 ^ { \prime \prime } and extracted the peak flux density of each source in each spectral window ( SPW ) to determine the spectral indices \alpha ( assuming I ( \nu ) \propto \nu ^ { \alpha } ) .
By cross-matching with catalogs of H ii regions , SNRs , PNe , and pulsars , we found radio counterparts for 840 H ii regions , 52 SNRs , 164 PNe , and 38 pulsars .
We found 79 continuum sources that are associated with X-ray sources .
We identified 699 ultra-steep spectral sources ( \alpha < -1.3 ) that could be high-redshift galaxies .
Around 9000 of the sources we extracted are not classified specifically , but based on their spatial and spectral distribution , a large fraction of them is likely to be extragalactic background sources .
More than 7750 sources do not have counterparts in the SIMBAD database , and more than 3760 sources do not have counterparts in the NED database .

Conclusions : Studying the long wavelengths cm continuum emission and the associated spectral indices allows us to characaterize a large fraction of Galactic and extragalactic radio sources in the area of the northern inner Milky Way .
This database will be extremely useful for future studies of a diverse set of astrophysical objects .