The manuscript uses 18 months of ICESat-2 repeat tracks to identify the grounding zone of the Antarctica Ice Sheet. It develops a method that could automated mapping the grounding zone and produces a grounding zone product that has nearly complete coverage of the Antarctica Ice Sheet. Elevation changes derived from ICESat-2 ascending and descending cross-over passes are also used for validation.

Given the significant increase in grounding zone density and the improved coverage, I believe that this ICESat-2-derived Antarctica grounding zone product will be of large interest to the cryosphere community. Furthermore, with more ICESat-2 repeat cycles coming out in next few years, the dynamic changes of grounding zone could be evaluated repeatedly and efficiently based on the automated techniques developed in this study. The manuscript is overall well written. I have no major comments except a few suggestions listed below. Therefore, I look forward to seeing this paper published in Earth System Science Data.

Specific comments:

Line 27: There is no ‘Point G’ in Fig. 1.

Line 37: Suggest adding a figure to show the schematic of grounding zone. This will clearly show where the point F, H, Im and Ib located.

Figure 2, 8 &13: The legend overlaps with the curve. Considering change the position of the legend for clarity.

Section 3.3.2: Hogg et al. (2018) also detected the Antarctica Ice Sheet break-in-slope point Ib using another altimetry data (CryoSat-2). I suggest the ICESat-2-derived Point Ib could also be compared to that product.

Reference:Hogg, A. E., A. Shepherd, L. Gilbert, A. Muir, and M. R. Drinkwater (2018), Mapping ice sheet grounding lines with CryoSat-2, Advances in Space Research, 62(6), 1191-1202.

This manuscript presents a high-resolution antarctic grounding zone product from ICESat-2 laser altimetry. The data presented in this manuscript is critical for assessing ice sheet stability, estimating mass budget and its contribution to future sea level rise of Antarctic ice sheet, and ice sheet model projections. This study could potentially make a valuable contribution to studying Antarctic ice sheet mass balance. However, I do not believe the presentation of the manuscript at this stage is sufficiently good to warrant publication. There are some issues with the manuscript that would be valuable to address.

Major comments:

1. In Sect. 2.5, the paper describes the operation of crossover analysis, not the method of GZ features extraction. Crossover analysis is mainly to validate the results. So, Sect. 2.5 should be merged into Sect. 3.2.

2. In Sect. 3.2, the paper mainly focuses on the comparison with ICESat-2 crossover measurements. However, there are many a lot of comparisons with other study, are mixed in. These comparisons are better to be move into in Sect. 3.3.

The paper is wrote well entirely. However, there are still some problems in English writing. It is suggested to revise the English description entirely.

Other comments:

1. In Fig 2,3,8 and 13, lines of different colors are difficult to distinguish, please try changing their linetype, thickness, or color. The legend covers the data, please adjust the position.

2. Line 161 and 219, (d.I,n) should be (d, i, n).

3. In Fig 7, 9 and 10, the data source of the mass chang used in the figures is not given in the manuscript. Why use mass change? Is ice velocity more appropriate here? Moreover, these diagrams do not show absolute separations very well. I suggest showing only the key areas as shown in Fig 11

4. In Fig, suggest adding a subgraph representing the location.