We present the results of the first sensitive L band ( 3.4 \mu m ) imaging study of the nearby young embedded cluster NGC 2024 .
Two separate surveys of the cluster were acquired in order to obtain a census of the circumstellar disk fraction in the cluster .
We detected 257 sources to the m _ { L } \leq 12.0 completeness limit of our \sim 110 arcmin ^ { 2 } primary survey region .
An additional 26 sources with 12.0 < L < 14.0 were detected in the deeper survey of the central \sim 6.25 arcmin ^ { 2 } region of the cluster .
From an analysis of the JHKL colors of all sources in our largest area , we find an infrared excess fraction of \geq 86 % \pm 8 % .
The JHKL colors suggest that the infrared excesses arise in circumstellar disks , indicating that the majority of the sources which formed in the NGC 2024 cluster are currently surrounded by , and likely formed with circumstellar disks .
The excess fractions remain very high , within the errors , even at the faintest L magnitudes from our deeper surveys suggesting that disks form around the majority of the stars in very young clusters such as NGC 2024 independent of mass .
From comparison with published JHKL observations of Taurus , we find the K – L excess fraction in NGC 2024 to be formally higher than in Taurus , although both fractions are quite high .
Thus , existing L band observations are consistent with a high initial incidence of circumstellar disks in both NGC 2024 and Taurus .
Because NGC 2024 represents a region of much higher stellar density than Taurus , this suggests that disks may form around most of the YSOs in star forming regions independent of environment .
We find a relatively constant JHKL excess fraction with increasing cluster radius , indicating that the disk fraction is independent of location in the cluster .
In contrast , the JHK excess fraction increases rapidly toward the central region of the cluster .
The most likely cause for this increase is the contamination of the K band measurements by bright nebulosity in the central regions of the cluster .
This suggests that caution must be applied using only JHK band observations to infer disk fractions in nebulous environments .
Finally , we identify 45 candidate protostellar sources in the central regions of the cluster , and we find a lower limit on the protostellar phase of early stellar evolution in the NGC 2024 cluster of 0.4 - 1.4 \times 10 ^ { 5 } yr , similar to that in Taurus .